Writer Jamie Mathieson explores the 2D and 3D worlds in his second Doctor Who script.

After the success of last week’s Mummy on the Orient Express, the fact that its writer would be penning Flatline was very welcome news. Could Mathieson replicate the success of his first episode? Yes, he definitely did. Flatline is simply superb, and ties for best episode of the series so far.

Flatline has Clara investigating monsters from another dimension that are terrorising Bristol, all while the Doctor is confined to the TARDIS after the monsters leech its dimensional energy, trapping him inside. Will Clara be able to save the world all by herself?

Original ideas on Doctor Who are somewhat of a rare occurrence these days – no surprise considering it’s been around for almost 51 years. But every now and then, an episode like Flatline comes along, and has a truly original premise; in this instance, monsters from a plane of existence with only 2 spacial dimensions attacking ours of 3. It’s an intriguing concept, and is pulled off very well here, with the ‘Boneless’, as the Doctor christens them, being extremely effective villains. Like the Mummy from last week’s episode, the Boneless actually do things and pose a real threat to the cast, instead of being shunted to one side in favour of something else, or forgotten about altogether. Their ‘gimmick’ also works well as a horror device – seeing people sucked into the walls and floor, then having their body parts displayed for all to see is a quite disturbing prospect. But another great thing about the Boneless is how they’re shown to adapt their attacks as the episode progresses, from simply being able to convert from 3D to 2D, then from 2D to 3D, and finally warping the two dimensional plane entirely until it resembles and functions like the 3D one.

But as great as the monsters were, they weren’t the only thing in the episode. Flatline was Clara’s time to shine as she filled the role of the Doctor while he was busy playing hermit crabs with the significantly diminished TARDIS. What’s interesting is that throughout the episode she seemed to be going through a checklist of things the Doctor would do. Recruit a companion, lead a large group of people away from a threat, promise to save everyone’s lives and invariably fail to do that. But the crux of this is towards the end, when the TARDIS needs powering up. Clara initially asks what the Doctor would do in this situation, but immediately corrects herself and asks what she would do instead. Exactly why she would seemingly reject the Doctor’s line of thought in preference for her own (in this instance, at least) is a bit unclear, but I think that perhaps she’s telling herself that she can solve problems independently, without any help from the Time Lord. Of course, it could also be simply because the Doctor wasn’t in a position to give advice at that time. But whatever the reason, I’m just glad that we could see Clara making these sorts of decisions by herself. And the actual resolution she came up with was, much like most of the episode, rather clever and imaginative, and one I definitely didn’t see coming. So well done Clara.

However, Clara didn’t manage to impress me 100%, and that’s due to her phone call with Danny Pink. I’ve been going on about how much I dislike Clara’s treatment of Danny thus far, so I’ll simply say that in this case, she probably should have ignored Danny’s call and set her phone to say that she was busy. After all, if she did it when Danny rung a second time, why couldn’t she have done it earlier and not have to lie to him again? Speaking of lying, the revelation that she deceived the Doctor at the end of Mummy on the Orient Express came as no surprise. I saw that coming as soon as it aired, but I’m glad it was resolved quickly, without dragging on for too long.

Another small problem with the episode is that the defeat of the Boneless feels rather rushed, and is completely unexplained. The sonic screwdriver once again comes to the rescue and makes the TARDIS do...what, exactly? The Doctor says that he’s sending the Boneless back to their own 2D world, but how he does that, and whether there’s anything stopping them from attacking humans again, we never find out. It would have been nice if we got some explicit confirmation as to what happened, and all it required was a few lines of dialogue. Get rid of the rather silly wannabe 11th Doctor speech that 12 gives before defeating the Boneless, and use the ~30 seconds of screentime to do some explaining.

But other than that, the episode's essentially perfect. Peter Capaldi is brilliant as usual, even with his limited screentime. His interactions with Clara without, especially the parts where he's communicating with her through the tiny TARDIS doors are one of the highlights of the episode, and part of me wishes that we could have seen more of him handing large objects to Clara through the small TARDIS when it's in her handbag. The supporting cast is great too, with Rigsy (Joivan Wade) being a stand out. I also liked how the unlikeable supervisor survived; it was a great way of subverting audience expectations as to who makes it out of an episode alive.

Overall, Flatilne is an excellent episode. With very well realised monsters, some great Clara moments, funny TARDIS moments and a solid supporting cast, a few minor niggles can’t stop it from being tied for the best episode of the Series so far.

9/10