'Planet of Evil' has fallen on hard times. Back when fans' only knowledge of old Doctor Who stories were hazy memories story guides like that in Doctor Who: A Celebration, 'Planet of Evil' was a terrifying story that drew on Dr Jekyll and Mr Hyde to great effect and was even compared to Alien, as a monster picked up on an alien planet slaughtered the crew of a spaceship. With the video release however, opinions became rather more divided, and 'Planet of Evil' was found by many to disappoint. But 'Planet of Evil' doesn't really deserve its poor reputation. Whilst it is overshadowed by the stories on either side of it, it still has much to offer.

Firstly, the jungle set, one of the story's most famous aspects, is pretty good. It looks suitably different from any jungle on Earth, and its rubbery vegetation gives it a very alien feel, which is enhanced greatly by the wise decision to shoot many of the jungle scenes on film. Indeed, Zeta Minor is one of the most unearthly alien planets seen in the series, with its weird foliage, non-reflective black pool and the Anti-Matter monster. The monster too is far more alien than many seen in the series, due to its appearance as a red outline (an obvious, but effective homage to Forbidden Planet), and the fact that unlike many intelligent aliens in Doctor Who it doesn't speak English, its only communication with the Doctor achieved through a surreal scene in a black void. 

Set amidst this alien landscape, Episode One gets off to a promising start. Sorensen sets the scene with his terse assertion that the planet is alive, and the deaths of the two Morestrans are dramatic and disturbing, as they vanish screaming in agony, only to reappear as quite convincing shriveled corpses. The sense of danger established in these early scenes is maintained throughout, with the Anti-Matter Monster and the Anti-Men well nigh unstoppable; the tension in Episode Four as the marauding advance through the ship and agonized screams are heard over the communications system, whilst the ship plummets back towards Zeta Minor is palpable. However, flaws start to appear in Episode One as the Doctor and Sarah are imprisoned in a room from which they can easily escape; admittedly the script addresses this, and it gives Sarah something to do since it is she who realises that with the failing power the magnetic window locks will have weakened, but it feels very contrived. 

I'm in two minds about the Morestran probe ship sets. They are very sparse, and this contrasts sharply with the jungle on Zeta Minor, and this makes a certain amount of sense since it further enhances the planet's alien feel and also military vehicles are not renowned for their décor. On the other hand, these sets are so stark and featureless that they are actually boring to look at, and ironically the comparatively moody lighting in the corridors makes them marginally more interesting than the command area. The Morestran costumes are also pretty awful, which doesn't help the story's visual appeal during the latter two episodes. 

In addition to these minor flaws, there are two aspects of 'Planet of Evil' that I originally considered to be weaknesses, but as the story progressed I found that, bizarrely, they actually added to the story. The first is the anti-matter plot line. As Kate Orman has pointed out, anti-matter does not cause people to turn into ape-men, it simply causes huge explosions in collision with matter. Initially, this makes this plot seem like pure technobabble, but then in Episode Two, during a conversation between the Doctor and Sarah, it is pointed out that matter and anti-matter in collision causes a massive release of energy (as seen in 'The Three Doctors'). Suddenly, by addressing this inconsistency, the script makes the anti-matter plotline seem less like technobabble and more like intentional fantasy, and in doing so adds further to otherworldly nature of Zeta Minor, subtly reminding us that this unique planet is a gateway between universes, neither entirely in this universe nor the universe of anti-matter. This also ties in with the Doctor's implication that if the Morestran ship manages to get too far from Zeta Minor with anti-matter on board, there will be a cataclysmic explosion that will threaten the entire universe, suggesting that Zeta Minor exists in a state contrary to the laws of physics. 

The second aspect is Salamaar. In my opinion, there is no evidence in Doctor Who that Prentis Hancock can act; he was wooden in 'Planet of the Daleks' and he's wooden here, although it doesn't help that he's playing very similar characters in both stories. Nevertheless, Salamaar the character is rather interesting. He's ludicrously unstable and clearly unfit for command, making reckless decisions and twice intending to execute the Doctor and Sarah simply because it will make his life easier if they are responsible for killing the Morestrans on Zeta Minor. When he eventually accepts the truth, he adopts a death and glory attitude, launching a suicidal and misguided attack on Sorenson that further endangers the surviving crew. Initially, I found it absurd that such an unstable character could become commander of a military expedition, but as the story progressed this too made me think; there are hints that Sorenson's influence back on Morestra will get him whatever he wants, and once these hints of corruption are sown it raises the obvious possibility that Morestra is so corrupt that Salamaar himself reached a high ranking position because of friends in high places. This is further supported by the fact that the much more competent but disruptive Vishinski holds a lower position, raising the possibility that his outspoken nature has harmed his career. 

The acting in 'Planet of Evil' is variable. Tom Baker and Elizabeth Sladen by now play their roles with ease, and the Doctor gets to be suitably impressive here, claiming that he is not without influence and proving able to communicate with the Anti-Matter Monster. Sladen is convincingly frightened at appropriate moments, especially the cliffhanger to Episode Three and during the final attack of the Anti-Men in Episode Four. Frederick Jaeger is superb as Sorensen, playing the tortured scientist with great emotion. Sorensen's initial obsession with his work is so all consuming that he blames the Doctor and Sarah for the deaths of his colleagues and strenuously denies both the Doctor's claims about Zeta Minor and also the transformation that he is undergoing. But Jaeger suggests that Sorenson is also troubled by his conscience, and his quiet confession to the Doctor in Episode four that "My hypothesis… was false" has rather a noble ring to it. In story terms, this admission seems to bring him redemption, and the Anti-Matter Monster unexpectedly cures him at the end of the story. Vishinski is also well acted by Ewan Solon, but the other Morestrans are utterly forgettable, with one or two (Ponti being a prime example) being quite bad. 

In summary, 'Planet of Evil' is flawed but effective and certainly doesn't deserve its recent poor reputation. In a weaker season it might stand out more, but as it stands it is overshadowed by both 'Terror of the Zygons' and the story that follows…

'Pyramids of Mars' is often accused of having plot holes. In fact, I can think of three potential plot holes, but only one of them actually bothers me, and that only slightly. The first of these is that the Osirans entombed Sutekh with everything he needs to escape, but this is obliquely addressed in the script, the Doctor firstly explaining that the Osirans' moral code forbade them from executing Sutekh and later telling Sarah that they had "cerebrums like spiral staircases" and were known for their guile and cunning. The implication is that leaving Sutekh with a chance of regaining his freedom is part of their moral code, and this is further implied by the fact that the traps in the Pyramid of Mars are dangerous but passable; certainly, this is the assumption made by Justin Richards in 'The Sands of Time'. The second supposed plot hole is that having Scarman build the Osiran war missile in England is pointless, since he could have constructed it outside Sutekh's tomb, but again this isn't really a plot hole, given that it makes sense for Sutekh to exploit the fact that Scarman owns a large and secluded estate. The third plot hole is that the Doctor is rather fortunate that Sutekh decides to travel to England to start his revenge, thus allowing the Doctor to destroy him, and it is this slight flaw that bothers me, since he could easily have destroyed the world from Egypt. On the other hand, he may have wanted to collect his remaining Servitors before launching his reign of death. But even if this is construed as a plot hole (it is undoubtedly a plot contrivance to allow the Doctor to triumph), it doesn't matter; 'Pyramids of Mars' is a story that confidently papers over its limitations with a great deal of style and atmosphere.

'Pyramids of Mars' is unusual (although not unique) in that every supporting character except for the briefly glimpsed Egyptians at the beginning is killed off during the course of the story. This is significant, because it demonstrates on a small scale the horror represented by Sutekh, as one after another characters are casually slaughtered at his behest. This works particularly well because Holmes and Griefer create characters that are uniformly well characterised, regardless of importance to the plot, so that every death has an impact. The first example is Collins, the old and weary butler who has remained in the service of the mysteriously absent Professor Scarman partly because he doubts that he could find a new appointment at his age, but probably also out of a sense of loyalty. He appears only briefly, but is rather likeable and Michael Bilton gives him a plaintive air that makes his death at the hands of the Servitors all the more traumatic. Warlock is an even better example, forcing his way into Scarman's house out of concern for his friend and paying the ultimate price, and his death also feels tragic, partly because he has survived being shot by Namin, but also because it is ultimately Scarman who orders his death, whilst under the control of Sutekh. The best example of this principle is Lawrence Scarman. Lawrence is superbly portrayed by the ever-reliable Michael Sheard, and lasts for nearly three episodes, during which time we see his almost childlike fascination with the Doctor's alien knowledge (the scene in which he bounds enthusiastically around the TARDIS is charming), and also his gnawing anguish over his brother's ghastly fate. His interference with the Doctor's attempt to block Sutekh's control of Marcus and the Servitors literally endangers the entire universe, but it is painfully understandable and it is hard not to feel sympathetic as guilt is added to Lawrence's emotional burden. His death at the smoldering hands of his brother is heart-rending, and because of this the Doctor's subsequent dismissal of Lawrence's death works so well in reminding us of the true scale of the threat posed by Sutekh. The usually compassionate Doctor is so focused on stopping Sutekh that he can't waste time with individual deaths, and this more than anything else in the story is the true measure of Sutekh's power. Even Ibrahim Namin's death is powerful, as this faithful servant of Sutekh is casual dispatched by Sutekh's puppet as a reward for his service, and the same is true of Marcus Scarman, as he briefly regains his freedom from Sutekh in Episode Four, only to disintegrate into a charred husk. 

Sutekh is vital to the success of 'Pyramids of Mars'. I praised 'Genesis of the Daleks' for its portrayal of Davros as one of Doctor Who's greatest villains by presenting him as a villain whose sense of morality is totally opposed to the Doctor's. With Sutekh, that principle is taken far, far further. He is perhaps the ultimate villain, a being of immeasurable power entirely devoted not to death or the subjugation of others, but to the total extermination of all life, everywhere, forever. His instruction to Scarman that after the missile is completed all life within the deflection barrier right down to birds, fish and reptiles must be destroyed because all life is his enemy is disturbing; no other villain in Doctor Who is so nihilistic. And whereas Davros is ultimately a man in a wheelchair whom the Doctor can physically overpower and in other respects face on an equal footing, Sutekh is effectively a God. The scene in which the Doctor confronts Sutekh in Episode Four is extremely powerful, Sutekh casually torturing him for every minor insult and explaining that all life must end under his reign. Gabriel Woolf's chilling tones drip with evil, helping to emphasize Sutekh's total malevolence, and mention must also be made of the rather sinister, but only briefly seen, jackal-like face beneath the impassive blue mask. 

If the human cost of Sutekh's evil is well conveyed by the deaths of the supporting characters, then the large scale consequences of his escape are served by the scene in Episode Three in which the Doctor takes Sarah to a 1988 in which Sutekh was not stopped. The brief sight of the blasted, lifeless Earth is highly effective, further demonstrating Sutekh's power without blowing the budget, and also implying interesting things about time travel, given that it suggests that the Doctor's defeat of Sutekh has always happened and is already a part of history even before he succeeds. 

The characterisation of the Doctor here also stresses the danger posed by Sutekh. Early on in the story, as Collins discovers the Doctor and Sarah, we get a fairly typical example of the Doctor's wit, as the butler demands to know how he got into the building; the Doctor cheerfully responds "Through the window. I understood the property was for sale?" However, as soon as the Doctor discovers the nature of his enemy, he is unusually grim throughout, and Tom Baker puts in one of his most intense performances. When the Doctor travels to Egypt to distract Sutekh, he fully expects to die in the process, but throughout the story he gives the impression that he isn't sure that can prevail here. Tellingly, once Sutekh is aged to death in the time corridor, he reverts briefly to his usually cheerful self, just before he and Sarah flee from the burning Priory. 

The acting in 'Pyramids of Mars' is very fine throughout. I've already mentioned Micheal Sheard and Gabriel Woolf, but Bernard Archard's performance as the living dead Scarman is very effective, and both Tom Baker and Elizabeth Sladen are on top of their form. Baker is convincingly agonized when Sutekh tortures him and as mentioned puts in a tense performance throughout. Because of this it falls to Sladen to lighten to the atmosphere slightly, which works because it suggests she can't fully comprehend the true danger posed by Sutekh whereas the Doctor can. She also gets to shoot at the gelignite on the ramp of the missile, thus contributing significantly to the Doctor's desperate (and as it happens, failed) gambit to stop Sutekh from destroying the Eye of Horus on Mars. 

The Mummies are another highly successful aspect of 'Pyramids of Mars', combining the unstoppable air of the Cybermen in their better outings with a distinctive and creepy appearance; in addition, the weird howling noise made by the Servitor that gets its foot caught in one of Clements' traps is rather spine-tingling. The whole production is very well made, with superb location footage, great sets (I especially like the strange swirling backdrops in the Pyramid of Mars, which creates an alien feel), and evocative incidental music. Overall, 'Pyramids of Mars' is a high point of the generally strong Season Thirteen and a real classic.

Terry Nation is possibly Doctor Who's most erratic writer. On the one hand he is capable of writing classics such as 'The Mutants', 'The Dalek Invasion of Earth', 'The Daleks' Master Plan' and 'Genesis of the Daleks', whilst on the other hand he is capable of writing such balderdash as 'The Keys of Marinus', 'The Chase', 'Planet of the Daleks', and, unfortunately, 'The Android Invasion'. Apologists for this story might argue that it seems worse than it is alongside the other stories of Season Thirteen, but personally I think there's so much wrong with it that placing it next to any other story, no matter how dire, is going to amount to little more than trying to polish a turd. 

'The Android Invasion' suffers from more plot holes than any other Doctor Who story I can think of. First of all, we have the replica of Devesham on Oseidon. This is immensely detailed and extremely elaborate, which raises the question, what exactly is the point of it? To explain what I mean, allow me to recap Styggron's plan. The Kraals intend to invade Earth and wipe out mankind using a virus. The virus isn't airborne and it kills its victims within seconds or minutes, which would limit its spread immediately, since anyone infected with it wouldn't have time to travel very far before dying. Metres, if they are lucky. Therefore, Styggron's androids are intended to "disseminate" the virus. In addition, note that Styggron insists that the extermination of mankind will take place within three weeks. Therefore, the androids will have to transport the virus to all parts of the planet within that time and physically expose everyone on Earth to it. This is, clearly bollocks; firstly, there are only a handful of androids, and secondly as soon as whole areas started dying in one go, quarantines would be enforced. Since there is no evidence that Styggron has facilitates on Earth to make new androids, this means that a group of androids who resemble the inhabitants of one small village are expected to evade quarantines without being noticed, which is also bollocks, and in case anyone is thinking of pointing out that they are allegedly indestructible, allow me to point out that this is twaddle, since Sarah electrocutes one (and their faces fall off very easily if they trip up). Even if we assume that this is possible, the androids would still have to spread out from Devesham on arrival, which raises the question of why Styggron establishes an elaborate program of training that involves the androids spending an afternoon in the local pub. The point is, the only possible reason for the needlessly elaborate Devesham mock-up would be if the Kraal androids were intended to infiltrate Devesham by replacing the inhabitants and then spend some time there gathering information. Which they aren't. Indeed, not only that, but they successfully replace the entire personnel of the Space Defence Station within minutes of arriving. The only remotely plausible explanation that is actually consistent with the witless plot is that the training ground allows them to become familiar with the layout of Devesham and the Space Defence Station, which in any case is provided to Styggron by Crayford. Some kind of map might have been easier…

In addition to these gaping plot holes, if Styggron wants to use the androids to wipe out mankind, why doesn't he just drop androids all across the planet from orbit, instead of bringing them all to Devesham? If he's so clever, why doesn't he just create an airborne virus? If he can't, why doesn't he just fill a couple of pods with the virus and dump it in the ocean, since Nation appears in any case to have misunderstood the difference between the words "virus" and "poison". The number of unanswered questions in this story are astounding; if the brain patterns taken by Styggron from humans are as detailed as he implies, why does the android Sarah not know that the real Sarah dislikes ginger pop and that she left her scarf with the Doctor? Are the dogs used to chase the Doctor and Sarah real dogs, and if so how did they get to Oseidon? If not, what are they for? If they are androids but are capable of following the tracks of the Doctor and Sarah, then why can't the other androids do the same? Waste of time making robot dogs, frankly. Why does the otherwise insanely detailed fake Devesham have stupid mistakes like the calendar with only one date in it? Why don't the androids in the pub grab Sarah in Episode One? If they're intelligent enough to realize that she could be part of some test, surely they're intelligent enough to bother to just hold on to her whilst they check with Styggron? Why, if most of the androids arrive at the pub in a truck before being properly activated, are some androids inside pods dotted around the village? Did they get bored and decided to play hide and seek? In Episode One, when Styggron tells Crayford that there might be rogue unit on the loose, does he catch a flicker of movement at the end of the corridor and immediately dive through a door to get at a gun? He can't possibly see that it is a stranger, and the androids are bulletproof. Well, probably: Styggron's claim that they are invincible is, as noted above, twaddle. To top it all off, the story ends with yet another notorious gaping hole as the Doctor uses a powerful electromagnetic field to jam the circuits of every android in the area, but then somehow manages to use his own android against Styggron. Apologists for this story might argue that this makes the Doctor look very clever, but given that he ahs only a few minutes in which to equip the android with a formidable array of shielding and reprogram it as well, I would argue that it makes Terry Nation look like a bit of an arse. 

Amongst all this rubbish, is there anything good about 'The Android Invasion'? Not really, no. The Kraals look quite good, but Styggron is basically a standard ranting megalomaniac with a mad plan, a line in gloating, and stupid dialogue ("Resistance is inadvisable!" Come back Professor Zaroff, all is forgiven…). Chedaki is voiced by Roy Skelton, who seems to have forgotten which of his roles he's in, as Chedaki sounds like bloody Zippy from Rainbow. Milton Johns is a fine actor, but Crayford is a ludicrous character; how on Earth he got the job of an astronaut if he's so paranoid that he assumes he's been deliberately abandoned when something goes wrong, and then agrees to help space Rhinos invade is a mystery, and then of course there is the notoriously stupid plot device of him never having looked under his eye-patch - does the man never wash?

The direction is adequate, the design uninspiring; the interiors of the Kraal base are forgettable and the spiky-bottomed doors just look daft. The whole set up in Episode One of the quite village with its inhabitants acting strangely is promisingly sinister, but delivers manure. Even the title is rubbish, suffering from the same basic weakness of 'Revenge of the Cybermen' in that its title undermines the mystery behind the first episode from the start. The regulars are fine; Tom Baker and Elizabeth Sladen are capable by this point in the series of playing their respective roles with consummate ease, and both tackle the feeble script well. John Levene and Ian Marter are also both their usual reliable selves, but they get little to do and it is therefore a shame that their last appearance in Doctor Who is in this story rather than the marvellous 'Terror of the Zygons'. Nicholas Courtney gets a particularly lucky escape in that respect, with the character of Colonel Faraday created as a stand in; Patrick Newell does well with what he's given, but the script paints him as a buffoon and the Brigadier had quite enough of that in 'The Three Doctors'. 

I'll end by pointing out one last plot hole; the Kraal fleet is poised to attack, but is never mentioned again after Styggron's death. In Episode Two, Chedaki tries to convince Styggron to abandon the androids, arguing that they are dangerous and that the Kraals can conquer Earth without them. Why then, do they not invade? The answer, and indeed the answer to all the plot holes in 'The Android Invasion' is actually quite simple: Chedaki and Styggron are lovers, but Chedaki is rather submissive; keen to please his completely loopy boyfriend, Chedaki humours his occasional plan to invade other planets even though they are ill thought out and obviously won't work. Once Styggron dies, Chedaki breathes a sigh of release and decides to quit whilst he's ahead, and/or goes home to Oseidon because he's too distraught to lead an invasion. Makes more sense than what we see on screen, anyway…