This review contains plot spoilers.

"You know Doctor, I can't tell if you are a genius or incredibly arrogant',.. "On a good day I'm both". - Perkins to the Doctor

What a romp and what a showcase for Capaldi. This was always the breed of story I hoped to get when Steven Moffat was first confirmed as showrunner. It has the heart of Doctor Who's golden period from 1974 to 1977 when Tom Baker was at his peak but also slots in very comfortably with a 2014 autumn schedule on a Saturday night. Doctor Who has often borrowed its own past successes and done something new, often to great effect. Thanks to a very capable director in Paul Wilmshurst (who continues to impress after 'Kill the Moon') and a more than competent script this is definitely one of those winners.

The story is remarkably simple without being too predictable. Various passengers from all walks of life on the Orient Express are being targeted by a remorseless creature that only they can see and feel. Despite their understandable panic there is only confusion from the people around them and nothing can be done within the span of Sixty-Six Seconds. And the Doctor realises that he is facing a stern test of his ability to come up with a solution. This is not a murder mystery for a Poirot or Marple and not everyone is playing by the rules..

The haunting killer of classic Who's 'Mind of Evil' is subtly referenced in the threat the Mummy presents - only the victims can see it . The way that it can move anywhere and not be stopped by physical items like bullets or locked doors is a perfect way to scare the junior members of the audience. The gimmick of having there be a visible counter remorselessly marking the moment of demise on-screen is somewhat odd but does come off - at least until Gallifrey's favourite son pulls off a beautiful trick (which doubles as an homage to Moffat's very first televised story).

The Orient Express is one of many in the cosmos and history, but this particular one rattles through the vacuum of space relentlessly, caring little for its appearance compared to other vessels that normally occupy this zone. It also used to be a tour through an area of the galaxy that had many a remarkable planet. However although this appears to be just another one of many journeys, there is a real twist when the whole vehicle is shown up as nothing more than a laboratory for testing a sample group. Although it is perhaps not totally watertight as the TARDIS has clearly broken into the environment!

What is clever is that quite a few of the victims are not all that likeable, or perhaps we catch them on a bad day. This is very welcome as it means that what normally is just monster fodder is something else and links in smoothly with the whole amoral presentation of this new Doctor which has fascinated many viewers since the season premiere. Also commendable is how the Doctor gets caught out several times - once when he casually mentions knowing a particularly memorable planet, now long-gone. This is put to effect later with an impact on the overall drama when the psychic paper turns out as not a simple plot short cut after all. The Doctor is realistically challenged, but such is his ego he will have none of it, and as bodies pile up his hubris and ruthlessness only seem to magnify.

When it comes to actually saving the day, it turns out to be a pyrrhic victory. A good number of people get back home unscratched. Some of the apparently threatened passengers were only hard light holograms and so were never really at risk. But lives are lost and not just to the sinister bandaged antagonist. Other carriages with real living people are broken into and the bodies are left to float in space, most likely forever. And this is a direct consequence of the Doctor's efforts: he does get the right end result, but only after a fatal trial-and-error procedure. The Twelfth Doctor may not react too overtly to this disturbing turn of events but he surely knows he could have done something different.

Guest stars are all up to the standards the better episodes have set previously, with a welcome cameo from talented singer Foxes and a nicely balanced guest role for Frank Skinner as Perkins. When he first appears there is ever so slightly an element of creepiness as appears rather indifferent to an old woman's death; but then perhaps he didn't take kindly to being looked down upon as was implied by what little we saw of her. I won't claim Skinner is as good an actor as he is a comedian but he still fits the particular role quite handily. Having Capaldi around certainly helps too as he effectively assumes the role of guest companion. His eventual moment in the TARDIS is also wonderful. The sheer exuberance that someone experiences from seeing dimensional transcendence is a trope I will never tire of. Meanwhile Clara is forced into another section of the train and interacts quite significantly with Maisie - herself a fine one-off character that very much needs saving by the Doctor.

Yes, she did not storm off after all, despite all the signs being there. Clara perhaps more predictably is the voice of morality again; with her friend admitting he could not do anything until he had all the facts at hand. That they are still together is a result of their deeply held admiration and respect. Purely liking one another as most platonic friends doesn't come into it, but then how many friends are there who are come from different planets and have such contrasting life spans?

Danny once again takes a backseat role the second week running, but the arc is still being explored in interesting ways. His seeming acceptance of Clara's hectic lifestyle and how the Doctor really cares on some level despite all his harmlessness is interesting if perhaps a little forced. I do welcome character development for this year's new star of Doctor Who and I am being won over gradually. However in all honesty I still find Samuel Anderson somewhat underwhelming in relative terms, especially if I were to compare him to Arthur Darvill who was rather similar in function.

Although the resolution sees the doctor disable the Foretold and use part of its core to save everyone remaining on the train, there is still no sign of the real threat who caused the crisis in the first place. This is a good idea and knowing Moffat there is as much chance that the answers come next season as they do by the closing twelfth episode of this present run of episodes. So we are left with a rock solid story that can stand up on its own and reward many a viewer's time, but also is well-woven into Series 8. I eagerly await the next Jamie Mathieson effort; conveniently enough it is scheduled for next Saturday evening.

This review contains plot spoilers.

Every now and again, an episode of Doctor Who comes along that divides and conquers at the same time. Kill the Moon could be that episode. It subverts expectations, and not just those of the viewer - nobody in this story gets what they expected either.

The episode begins with a quick scene-setting moment of Clara and 'disruptive influence' Courtney Woods on the Moon in the year 2049, broadcasting a message - they have a terrible decision to make. We then flash back to the present day at Coal Hill School, where Clara is giving the Doctor a piece of her mind for taking Courtney for a spin in the TARDIS at the end of The Caretaker, then telling her (off-screen) that she's "nothing special". Suddenly faced with an unhappy companion and a clearly distressed teenager, the Doctor makes the snap decision to take Courtney to the moon to try and make up for it, with Clara still on board. They arrive, not on the Moon, but on a dilapidated space shuttle heading very rapidly for it. A space shuttle full of nuclear bombs.

They are confronted by Captain Lundvik (Hermione Norris), and her two crewmates Duke (Tony Osoba) and Henry (Phil Nice). Lundvik's crew are on a desperate mission. The Moon has put on weight, and the Earth is being crushed under the pressure. Humanity is at the brink of extinction. Space travel at this point is in the doldrums, the last mission to investigate was ten years previously, and the Mexican crew disappeared without trace. Lundvik's crew have liberated a shuttle from a museum and are there to destroy the Moon. Norris is good as Lundvik, who comes across as cold and calculating, but in reality is a desperate, numbed woman on a suicide mission. Her cohorts, sadly don't get much to say or do. If this was Star Trek, they'd be wearing red shirts.

The Doctor is instantly on the case, noting that there is gravity where there should be none, and that the Moon is breaking up already. They investigate the base set up by the Mexicans, only to find it deserted except for cobwebbed and space-suited corpses. New Director Paul Wilmshurst wastes no time with the scares - there's something hiding in the shadows of the moodily-lit base, and in craters, some rather nasty spider-like creatures that make short work of Lundvik's crewmates. There's a brilliantly tense scene where the Doctor and co. attempt to escape a 'spider', and Courtney is trapped on the ceiling of a room with one when the gravity fails. The Doctor of course gets her back on the ground, and Courtney herself deals with the creature, but this is when the story starts to change from a straight scare-fest into a very different beast, from Philip Hinchcliffe scares to Malcolm Hulke moral grey areas.

It's all getting a little too real for the clearly scared Courtney, who asks to go home. The Doctor doesn't put up much of a fight, but locks her in the safety of the TARDIS while he continues his investigation. Ellis George is very good as Courtney. A whole episode of a teenager snarking in this scenario would be annoying and unrealistic - she shows that she's scared and cares enough about the situation to want to help, but even in the face of armageddon the shields are up, and she prefers to call Clara 'Miss'.

Paul Wilmshurst's direction is exemplary. He makes stunning use of the Lanzarote location as the lunar surface, and will doubtless traumatise a fair few youngsters with those vicious, screaming spiders. More from him please. New writer Peter Harness is also a real find, deftly handling scary and weighty with enough room for a joke about tumblr which other writers may have made into purest driven cheese.

The spiders are actually a form of bacteria, and the Doctor soon realises that the Moon isn't just a pile of rock orbiting the Earth. It's an egg, an egg with a very long gestation period - and it's hatching. A unique baby is about to be born.

Lundvik still wants to know how to kill it. Humanity is still at risk. Clara and Courtney insist that it's wrong to kill a baby. Clara turns to the Doctor to make a decision. And he walks away, disgusted with Lundvik who has primed the bombs, but adamant that this isn't his decision to make, snapping that it's time to take the stabilisers off the bike, and leaving the three women forty-five minutes to make a decision. Doctor Who is tackling abortion, and the Doctor has abdicated his responsibilities.

Clara puts it to the public vote. Humanity predictably chooses itself, but at the last moment she hits the abort button, and the Doctor reappears and whisks them back to Earth, where they witness the creature's birth from afar. You don't quite get a good look at it, which leaves something to the imagination. It lays a new egg to replace the old one before it flies away in peace.

Wrap up time.The Doctor makes a stirring speech about today being a turning point for humanity. Lundvik thanks Clara for stopping her from destroying an innocent life. Courtney heads for double Geography in the knowledge that she was the first woman on the Moon. All's well that ends well. Except when it doesn't.

Clara has been fairly subdued throughout, but is furious with the Doctor for leaving her with such a huge decision that she could so easily have got wrong. He gently tries to convince her that he knew she would always make the right decision, but it doesn't wash with her. He's patronised her and scared her out of her wits, and she makes a good point - he walks our world and breathes our air, so when we need him he bloody well needs to be there for us. The exchange ends with Clara telling the Doctor to go away and stay away.

Capaldi and Coleman are both excellent. The Doctor is still blunt, rude, and difficult, but he shows a slightly softer side towards Courtney and shows no hesitation in rescuing her, and a certain manic glee as he rushes around investigating. Likewise, he's warmer than usual towards Clara and clearly trusts her to make the right choice based on her character and his bluffing about history, despite how it backfires for him. The fangs are out however, when he makes his comment about the bike stabilisers. This Doctor feels he was in the right to step back and let history decide itself, and feels vindicated when the creature swoops off and the crisis is over. It's a bold choice to let the Doctor do this, clearly the 'Am I a good man?' arc is heading somewhere. How much of this he'll take on board is anyone's guess, but I'd imagine his mind will be well and truly made up by episode twelve.

Coleman, meanwhile, is notably less bubbly than usual for the bulk of the story, but is startling at the end. We've seen a tearful Tegan Jovanka say that it's not fun anymore, and a brave-but-upset Martha Jones leave the TARDIS to be there for her traumatised family - but Clara's scathing fury at the Doctor is something new. Leaving was never like this before. And it really feels like goodbye.

A brief coda follows, with Clara pouring her heart out to Danny, who tells her that if she was really done with the Doctor, she wouldn't be so angry. This feels tacked-on, doubtless to give a note of hope that Clara will reconcile with the Doctor, (of course she will) and to give a little hint to the continuing mystery of Mr Pink's army days - but personally I feel this takes away from the brilliant scene that precedes it.

Anyway, this quibble aside, this is an excellent, thought-provoking, and very grown-up piece of Doctor Who. It's not a comfy ride - and it's sure to prove divisive from its themes and the Doctor's vanishing act, but it's fair to say the stabilisers are off for this one.

Before we get to Peter Capaldi’s seventh episode as the Doctor, Kill the Moon, halfway through the season would seem a good time to see what we’ve learnt about the Doctor. Not surprisingly, nothing is cut-and-dried. If anything, every episode thus far has shown a different side to the Doctor, and a different mood, not all of them pleasant. In fact, they’re mostly bad moods, but that’s not necessarily a negative thing. Let’s have a look at the first six episodes, and the moods the Doctor displays.

Deep Breath: Angry Doctor
In his first story, the Doctor is angry for a number of reasons: he’s just regenerated, he’s confused, and he’s not happy with an older face – especially those eyebrows (but he quite likes the new accent). He’s experienced some memory loss, he’s not sure how to relate to people, most importantly Clara, but by the end of the episode, he’s calmed down enough to know he needs Clara’s friendship – and he asks her for it too, with a little help from his previous self’s phone call.

Into the Dalek: Cold Doctor
While the Doctor finds the thought of a good Dalek confronting and challenging, his focus on the mission to go inside Rusty and ‘fix’ it is very tight, and he can’t spend time showing compassion or grief when Ross is killed by the Dalek antibodies. He’s removed, emotionally distant, and even he isn’t sure if he’s a good man. It’s all a mask, of course, to protect him, in the same way his previous selves used bravado and gleeful excitement as masks, but not as endearing.

Robot of Sherwood: Grumpy Doctor
This less-than-endearing Doctor continues here. He’s disappointed that Clara wants to meet a legend rather than a real historical figure, and he’s irritated by Robin Hood, his merry men and their laughter and banter – maybe it reminds him of his previous selves’ modus operandi. And he’s annoyed that he’s proved wrong about Robin Hood. But then at the end, he drops the pretence, and we see the unwilling hero behind the mask.

Listen: Scared Doctor
The mask drops further here. There is something under the bed, it scares the Doctor because he doesn’t know what it is, and he doesn’t like that. So he sets out to find out what it is. Rather than putting himself on the line, he uses Clara to explore this universal dream. Thanks to her distraction though, it’s Danny Pink who’s the unwitting subject, until Clara is taken to the Doctor’s own childhood and his own fears.

Time Heist: Driven Doctor
In the same way the Doctor did in the Dalek mission, he takes control of the bank heist and assumes command, seemingly unconcerned by the other team members’ feelings. He’s not sure who the Architect is, and why they’re breaking into the bank, but he knows they’ll only find out by completing the impossible mission at any cost. Luckily the actual cost isn’t that dire – something that he himself set up, and once again, showing that under his brittle exterior two very compassionate hearts still beat.

The Caretaker: Jealous Doctor
While he goes undercover at Coal Hill Secondary School, ostensibly to see k out the deadly Skovox Blitzer, the Doctor is secretly investigating Clara’s private life, specifically her ‘boyfriend’. And he gets that wrong too. He knows, despite the feelings he still has (and can’t quite express) for Clara, regardless of his regeneration, he’s not her boyfriend, and won’t ever be. But he still wants her to be happy. That’s why he looks at Adrian and sees something of his previous self, and assumes that this is Clara’s love interest. He’s not happy when he discovers Danny is her actual boyfriend, and he’s jealous. Because he doesn’t like military men and takes an immediate dislike to Danny, and because he believes Danny’s not good enough for Clara – something that Danny challenges him on.

The Impossible Girl
But enough about the Doctor. Let’s talk about Clara. What does she think of the Doctor? Because she really is the voice of the audience, whether they are hardcore fans or just casual viewers. In Deep Breath, not only do we see her struggling to accept this new/old face of her friend, but it’s addressed overtly, specifically in the conversation she has with Madame Vastra about veils and perceptions. In subsequent episodes it’s obvious that she still enjoys travelling with the Doctor – with reservations – but she’s not yet ready to let Danny in on the secret, at least until she is forced to in The Caretaker. She is, like the audience, slowly getting used to this new Doctor and his moods. She may not like everything he says or does, but she remains faithful to him and is willing to give him a go. And that too is made obvious in Time Heist, when Psi notes how often she excuses his bad behaviour. And with Danny in the picture now, we’re seeing a more complex Clara. She’s not just the perky cheeky Impossible Girl – she too has her secrets and faults.

In the Pink
As for Danny Pink, he’s a character that’s developing quite nicely. Cast from the same mould as Mickey and even Rory, but with more baggage and backstory, it didn’t take him long to work out the Doctor, and seeing that develop will be quite the treat. So bring on the next six episodes and let’s see what else we learn about the Doctor, Clara, Danny – oh, and Missy too…

Clara Oswald had been doing a good job of leading a triple life lately, but something had to give.
She was already a teacher of unruly teenagers at Coal Hill, and assistant/carer/conscience to a newly unpredictable Time Lord to start with. As if those two factors weren't enough to contend with, now she's in a new relationship too, with Danny Pink. She's struggling to keep them separate, as she careers breathlessly between adventures and dates. She's eating two dinners in a row, going for a run after running down corridors, fishing seaweed from her hair. She's flagging. The control freak in her is working overtime trying to keep her worlds from overlapping. She seems slightly uncomfortable that the kids all know about her and Danny. She really doesn't want the Doctor and Danny even knowing about each other. So, when a very familiar looking relief Caretaker shows up in the Coal Hill staff room, she's appalled, and Danny instantly suspects that Clara already knows this man...

The Doctor is being proactive again, and has decided to go 'deep cover' to sniff out the threat. His version of deep cover is to basically put on an overcoat. His latest incarnation can't be bothered to try and fit in with the natives, particularly the P.E. Teachers. He makes angry signs, disrupts lessons, and even breezily shows pupil-with-attitude Courtney the TARDIS interior. Imagine if this incarnation had been the one exiled to Earth, he would have gone stir crazy. The Brigadier would probably have had him locked up next to the Master.

The threat is the deadly robotic Skovox Blitzer, drawn to the area by decades-worth of artron energy. It's a curious thing, another lone-gunman, a diminutive metallic soldier awaiting orders - scurrying around like a toy Racnoss. It's certainly very good at blowing things up - and people, like that poor Policeman, who meets a grisly end.

It's not a great villain, and although the design is novel, it's hard to believe that this critter could really take out the entire world. This series is getting quite robot-heavy. That said, this story isn't about the Skovox Blitzer. It's about the Doctor and Danny's relationships with Clara, and how they meet and reluctantly reach a grudging respect for each other, despite this Doctor's pronounced dislike of soldiers, a theme that has been prominent in this series, and looks to continue. 

The Doctor and Danny predictably clash, it's an interesting clash too, as normally when presented with a boyfriend figure it's not so much of a fair fight. Danny, being more of an alpha male, gives as good as he gets. Clara, meanwhile, doesn't end up having to choose between the men in her life, but does blurt out that she loves Danny. This, and Danny's inevitable role in the resolution help his case with the Doctor, who wants to know she's with someone good enough for her. Danny, meanwhile, wants to know Clara is safe. Although all three are at peace at the end of the episode, there's clearly something building, and we're probably due some turbulence and heartbreak soon.

Capaldi, Coleman, and Anderson are all excellent in this. Capaldi gets some zingers from Gareth Roberts and Steven Moffat's very funny script, and also the chance to run the gamut from boredom, rage, and a knowing little moment of vanity when he mistakes another teacher for Clara's boyfriend. His Doctor also gets to bond with the equally bolshy Courtney, who's back next week for a trip to the Moon, where bad things are likely to happen. Jenna Coleman gets better and better every episode, Clara continues to come into her own, and her chemistry with Capaldi is a joy to watch. She's equally good in a quieter way with Anderson, who continues to knock it out of the park with a subtle, well-judged performance.

The only criticism? More threat next time please. Although, looking at the teaser for next week, there's unlikely to be a shortage of that. See you on the Moon.

The Doctor and Clara are drafted in by a mysterious figure called the 'Architect' to rob the bank of Karabraxos - one of the most secure and dangerous monetary institutions in all the universe. Along with a cyborg /human hybrid named Psi (Broadchurch’s Jonathan Bailey) and a mutant shape-changer called Saibra (The Smoke's Pippa Bennett-Warne) the chase is on to secure something of great value. And just as vitally: to understand why all four of them have had their recent memories erased by their own volition!

Once again events are set in motion by a telephone call made to the Doctor's Tardis. Clara is thinking of her next meeting with Danny, but a normal life with romance is not that simple for someone who assists the Doctor in his adventures.

A clever edit is made to a later point in time, with amnesia being deliberately chosen by the four bank robbers. All of this comes together to form a very snappy and enticing pre credits sequence. Steven Moffat knew this opening would be a cut above the average and has gone on record as saying as much. It would be a real shame were the casual viewer to miss the start time by five minutes and be left to wander what is going on a little too much.

The two 'extra' companions on this mission both are easily distinguished. Psi is a die-hard gamer with a somewhat shaky record in staying on the straight and narrow. Rather endearingly his half-computer status results in his voice being prone to switching to a robotic tone under stress. His record of theft plays into a big crescendo of decision making as the episode really clicks into top gear. And shape shifter Salibra has some back-story she'd rather keep to herself. Despite a kindly persona she is rather unsettling in being so conversant with assuming others' visual identities. All the same, her special ability is crucial in order for the Doctor's party to casually walk into the Bank with their express aim of pulling off the 'heist'.

Alien creatures stand out in this colourful instalments. Memory worms are an unsettling but actually benign 'cameo' monster, whose function is actually to introduce the conceit of a gang of four who must figure out why they are suddenly together. The main alien creature, the Teller is a more important new addition to Doctor Who's huge menagerie, and has something of a minotaur aspect to its design. Although in some ways this foe is similar to the entity from 'The God Complex' it is also very different at the same time. The sequence in which an apparently dodgy businessman pays a heavy price for his misdemeanours relating to the Bank is a very effective 'behind the sofa' sequence. Although little is known about this somewhat unfortunate victim the scene ends up being simultaneously dark satire and sheer horror. There is also an uttering by the Doctor of the word 'soup' which will stick in viewers' minds. Peter Capaldi certainly knows how to make the most mundane sounding sentences have an edge to them.

The Teller's main role as a brain eater is sufficiently scary and memorable. However there is no question that the most malicious and cruel antagonist is villainess Miss Delphox - played by Keeley Hawes (Ashes to Ashes). We are even led to have sympathy for the monster, as it is harnessed to cause damage to enemies of the Bank, by being kept in either chains or in a form of cocoon. Furthermore Delphox manipulates the Teller to dispose of a nuisance individual or two and describes the action as 'account deleted' and generally struts about the Bank giving out orders in a nonchalant way. Evidently the Doctor will have to use his keenest wits to come up with a solution against such an antagonist.. except the finale has a twist where our Time Lord icon gets help from the most unlikely of sources.

Given the title of the episode the actual 'Mission Impossible' material is given suitably sufficient screen time to build up, and then pays off in a fluid and engaging way. The uncertainty over the Architect's identity and whether he is someone to dislike is well done and the eventual twist over his motives is certainly one which may surprise the viewer; although I would imagine a certain number can perhaps be ahead of where Moffat and Thompson had imagined the general viewer to be.

The regulars are once again very enjoyable to watch. Capaldi is still growing from episode to episode, and I sincerely hope he will stay the standard three years in the title role if not substantially longer. He can go from being icy-cold to bubbly and optimistic in a heartbeat, and he is so definitively alien. Even with a cyborg and shape shifter for company, he stands out like a mega-watt light bulb. Many lines of dialogue feel so well-suited to him, and he gets to emphasise why his distinctive eyebrows should afford him 'authority'.

Clara is now somewhat back to traditional companion territory like a number of her episodes in 2013, but still the after-effects of episodes like Deep Breath and Listen are here to stay. The Doctor's expression makes clear that sees her as someone not to talk down to although he very much wants to be the leader and the one to inspire others to greater heights. And yet the emotions conveyed in the Robin Hood episode are also on show - right at the end of the story, as the Twelth Doctor displays a fit of pique and childishness. Overall both leads' performances make clear the various levels upon which The TARDIS crew dynamic works on.

I did think on seeing the name of Steven Thompson that this could be a somewhat flat episode like 'The Curse of the Black Spot' and 'Journey to the Centre of The Tardis' were. Instead this is perfectly solid and engaging and feels just right in its one-part/ 45 minute format. One nitpick I have is that the Doctor tells Clara not to 'think' in a manner reminiscent to combating the Weeping Angels. More importantly the main humanoid villainess just doesn't make a strong impression. Keeley Hawes is a stellar performer normally yet seems to have been landed with a poorly sketched character and doesn't really get out of second gear given her enormous talent. "Intruders are most welcome" is one example of a quip from Delphox - it just would have been good to have an actual story behind her as well as some malicious wit.

But nonetheless there is a very good final confrontation with the Doctor meeting 'the Director'. Belated exposition plays its part, even as the surrounding location becomes a threat in itself. The urgency of the Doctor's assertion of full knowledge - and determination to end the problem - makes this a very well paced and fulfilling final act to the episode. And the revelation behind the Teller is a fine scene, both poignant and logical given the other information from earlier.

Overall then this is a solid joint writing effort from Stephen Thompson and Steven Moffat; with perhaps their prior collaboration on 'Sherlock' allowing for a keen sense of what to bring out from one another. With frenetic action, satire, a surprise twist or two, and good lively direction this episode is to be enjoyed much in the same manner as those that preceded it in Series 8.

Occasionally an episode of Doctor Who comes along that makes you think differently about the show’s parameters: what it can do, what it can be, and what it can mean. Described by Steven Moffat as a “chamber piece”, this looks like a money-saving installment, focusing predominantly on the main cast of regulars, with no guest stars to speak of and no (visible) monsters. On paper, it's an odd idea. In fact, this doesn’t sound much like Doctor Who at all (even if it has a kind of precedent going back to 1964’s ‘The Edge of Destruction’).

Yet 'Listen' is a strong candidate for the most intricately structured 50 minutes of Who ever. Near the episode's beginning we see the Doctor in Clara’s mirror, reflected three times over, and it’s an image that prefigures three journeys into characters’ pasts and futures, along with three fragments of childhood or child-like fear. 'Listen' is rammed full of Moffatisms: there are fairytale rhymes, things you can’t look at but can only sense or glimpse, child characters who are given prominent roles, and non-linear storytelling with timelines jumbling, jumping and stuttering. But 'Listen' is much more than a showrunner’s reprise: it isn’t simply this year’s ‘Blink’, for example. For one thing, it doesn’t (quite) deliver a new monster – instead it questions what monsters do, and what functions they can serve, for those who pursue them. Very often in Doctor Who, monsters represent something; they’re allegories or symbols for a range of anxieties. 'Listen' purifies that strategy, boiling Who’s monsters down to their simplest, starkest essence: an experience of fear and a desire for knowledge.

Of course, it’s tempting to see ‘Listen’ as a meditation on childhood; a piece of pop psychoanalysis where our favourite Time Lord can be understood though a very briefly sketched childhood trauma, and where the child is all too obviously the father of the man. But at its crucial moments, ‘Listen’ isn’t about childhood at all: it’s more about parenting. The Doctor shouts at Clara, ordering her to safety as he prepares to confront his own fear and his own need to know: he asserts tough patriarchal authority, positioning Clara as a child who can't evaluate own best interests. But the ‘impossible girl’ is also given a maternal if not matriarchal role, later informing the Doctor that he must do as he is told (something he recognizes and submits to). 'Listen' is, at least partly, about knowing when to heed authority and when to listen to a parent’s protective voice. It is, finally, not the Doctor who’s given an omniscient voice-over; it's Clara who watches over him, as if parentally, and Clara who ties together the episode’s themes as one culminating object is threaded through two different childhoods and a family inheritance. The same image, the same material artefact, seemingly gives rise to “Dan the soldier man” and the Doctor that we know; each becomes a distorted mirror image of the other. Scared may be "a superpower", but that superpower is both metaphorical and literal in the current Doctor Who universe, refracted in different ways through Danny Pink and the Doctor.

Fear and the unseen monster – the “figure”, as closing credits dub it – are equated; each stands as a sort of constant companion. But there are other equations that are more subtle and even more intriguing. What are the two things that this episode refuses to show us clearly? The monsters that must never be seen… and the young Doctor, reduced to a silhouette and a curl of hair. Neither the monsters nor the child-Doctor can be clearly apprehended. The monster’s power – its hold over the imagination – stems from remaining invisible; it is an empty space, a blank Rorschach test onto which anything can be projected. But the proto-Doctor is equally withheld; for all that this story seems to stretch the show’s boundaries and format, it refuses to convert the unseen Doctor into a prosaic face and figure. Resisting realism and refusing representation, the young Doctor is just as mysterious as the perfectly hidden creatures, and hence he remains just as much a space for projection, imagination and fantasy. The Doctor and the monster: both are rendered dream-like and oneiric, shimmering at the edges of perception.

Douglas Mackinnon directs this evocative material with aplomb, having recently been responsible for half of Line of Duty 2, which itself featured a stellar performance from Keeley Hawes (gracing the ‘Next Time’ trailer here). Jenna Coleman and Samuel Anderson both shine in their Coupling-style flashforwards/flashbackwards romance, with Anderson also convincing in the dual role of Danny/Orson Pink. But for me this episode belongs to Peter Capaldi. He’s mesmerizing when speaking out loud to himself, and looks alarmingly demented at moments, as he seeks to uncover what’s “under your bed”. This is cerebral, provocative Doctor Who at its very finest (where provocative is probably ‘scary’ for deep people). And it features one of the most unusual missions in the series’ long history: this Doctor isn't seeking to overthrow an oppressive regime or repel an alien invasion. No, he wants to engage in the interpretation of dreams, unusually allowing the TARDIS to travel via 'subconscious' means.

To worry about continuity seems to miss all the poetry of this episode. Perhaps some devotees will feel that the Doctor’s early years should have stayed firmly off-screen, or that Clara is being given too much sway over the Doctor’s identity here – she seems to symbolically create “Dan” and the Time Lord: soldiers whose power to protect is rooted in fear. Perhaps others will worry about how the TARDIS can so easily find its way to that barn, and that tearful child. But if 'Listen' plays on certain fan fears (of a Doctor that isn’t quite heroic or mysterious enough), then it does so in order to find new possibilities in the programme’s storytelling engines, and to worry away at fixed images of 'the hero'. In The Inner World of Doctor Who, Iain MacRury and Michael Rustin suggest that the Doctor can often be interpreted as a kind of “inadvertent therapist” (p.290), listening to others and helping them remake and re-order their lives. Here, though, it is the Doctor who is analysed by a script that ranks among the show’s most experimental explorations. What really lurks under the Doctor's bed? This is Doctor Who that demands to be thought about. It’s the programme’s format rewritten and yet perfectly encapsulated at one and the same time. And it leaves us with a beautiful image: the good enough hero as a kind of broken soldier.

The economical, sparse and interlocking structures of 'Listen' – treating continuity as a space for creative play – potentially make this Steven Moffat’s best Who script to date. It’s about striking images rather than spectacular effects; it’s about what it means to be scared, rather than cool and merchandisable monsters; it’s about “real, inter-human” date stuff just as much as the end of time, and it’s about the productive, transformative work that dreaming can sometimes perform. Rupert’s dream which gives rise to his new self may be implanted by the Doctor, in a sense, just as the Doctor’s own 'dream' of himself is seeded by Clara, but these science-fictional suggestions nevertheless stress the importance of our interior lives and dreamscapes. The Doctor’s interest in a seemingly universal dream (and its interpretation) ultimately gives way to dreams of a better self.

On paper, this might not sound quite like Doctor Who. Perhaps this ‘Fear & Monsters’ riff amounts to Moffat’s ‘Love & Monsters’ moment, and may be it’ll prove to be just as divisive. But watch ‘Listen’ without prejudice, and you’ll find series eight of Doctor Who humming with a darkly glittering and serious brilliance. We’re past the fiftieth anniversary, but there are still new things, as raw and energising as childhood fears, to be said and heard through the medium of Who.

There can't really be an 'instant classic': classics take time to settle into fan consensus. But if such an entity existed, and if it could be glimpsed, then 'Listen' would surely deserve the title.