Flatline

This review contains plot spoilers.

Nine weeks in, and it's time for a 'Doctor-lite' episode, as Clara Oswald's journey continues. Last week, in Mummy on the Orient Express, we saw her consider her role as the Doctor's companion post-wobble. This week, she's had a shock promotion - it's her turn to be the Doctor.

Arriving on present-day Earth, we're immediately in uncharted territory for Doctor Who - Bristol. They should have taken the time to look up Chris Parsons, and see if he moved back to the area after all that business with Skagra and that sphere in Cambridge. Hopefully he'd live in the nicer part of Bristol, which we don't see here. The TARDIS arrives on a wasteground, and the first place Clara visits after that is a dingy underpass. Other locations include a warehouse and a railway tunnel. It's not doing Bristol's tourism industry any favours.

After a brief, creepy teaser, the story quickly gets down to business - the TARDIS is rapidly shrinking with the Doctor trapped inside, and lunch with Danny Pink is off. Clara is left to investigate, with the trapped Doctor as backseat driver - giving her the sonic, an earpiece and hacking her optic nerve.

Clara soon happens upon a Community Service team led by nasty-piece-of-work Fenton (Christopher Fairbank), and teams up with one of the group - Rigsy (Joivan Wade), a likeable young man with a penchant for street art. From the start Rigsy is portrayed as a good sort, while Fenton is an unrepentant bigot and bully throughout, and nearly gets everyone killed. Even the Doctor's moved to say that not all the right people were saved at the end.

Fenton's crew are tasked with painting over murals that have appeared alongside tributes to recently disappeared locals. The murals are of people with their backs turned. It soon transpires that they're not murals. A sinister alien force is at work - one that exists only in two dimensions. It's dissecting and analysing us, a slow-dawning realisation that hits when the Doctor twigs that the strange decor on the walls of the flat of one of the missing people is actually a flattened out human nervous system.

The alien threat is unnamed, doesn't speak, and has unknowable, yet nasty motives. We never learn anything about it - even whether it's a single entity or a race - but its theft of our dimensions, and our image is a disturbing concept. The concept of people turning into drawings was of course done way back in Fear Her, but there's no upbeat reversal of the situation here. The Doctor is briefly given pause to ponder whether the aliens' (or alien's - we don't know for sure) M.O. isn't necessarily bad, but his mind is made up by the end, and his fury is something to behold. The stop-motion-styled flowing effect as people are absorbed into the walls and floors is creepy, as is the jerky, misshapen movement of the painted figures chasing down the railway tunnel. Once upon a time Doctor Who made kids afraid of shop window dummies, telephone flexes, and statues. It recently branched out to bedsheets. Now it's moved on to walls, and floors.

Douglas MacKinnon does an excellent job of directing as ever, all long shadows and atmosphere, with some excellent camera trickery and physical comedy - as the Doctor's hands and face portrude impossibly from the shrunken TARDIS. Clara even pulls a sledgehammer from her handbag. Jamie Mathieson delivers his second cracking episode in a row - more from him please.

Danny Pink appears again, in another cameo - the third in a row since his last full appearance in The Caretaker. It's hard to see where his character is going from this, and Samuel Anderson's a bit wasted here - hopefully his story will finally pay off in the next few weeks.

For a Doctor-lite episode, the Doctor is much more present than usual, albeit trapped in an ever-diminishing TARDIS. Capaldi and Coleman continue to impress. Both get some great lines, and the Doctor and Clara's relationship is now in a very interesting place. She's thoroughly pleased with herself about how well she handled standing in for the Doctor. She wants his approval. He eventually compliments her, but seems a little troubled at how well she did at 'being' him, and also at how easily she lies to Danny about still travelling with him. Perhaps his influence isn't healthy, and he seems to acknowledge this.

We end by cutting to Missy, watching Clara (somehow - how does she do that?) on her white iPad, remarking how glad she was to have chosen her. We'll find out what for in a fortnight, but it's unlikely to end well.