After all the Dalek-Davros-Missy shenanigans which probably stretched continuity to breaking point last week it’s nice to have a standalone adventure. And pleasingly this one harks back to the well-established Base Under Siege template that became a staple of the show back in the 1960s mainly during the Patrick Troughton years.
The crew of a twenty-second century underwater base located under a lake on the site of a flooded village have recovered something that looks like an alien spacecraft. As they investigate it a ghostly figure appears. It activates the engines of the ship which kills the base commander. Then the base commander appears as a second ghost.
The Tardis materialises on the base and the Doctor and Clara encounter the ghosts. There’s a nice bit of business with the ghosts attacking the Doctor and Clara with an axe and a harpoon gun that they can just about manage to hold despite being mostly incorporeal.
The Doctor finds the other members of the base crew hiding out in a faraday cage, a room with electromagnetic interference. For some reason it prevents the ghosts from getting inside. Another interesting fact is that the ghosts only come out at night. “Night” being an artificial night from the day-night rhythm the base uses.
And somehow these ghosts are interacting with the technology of the base. They manage to turn “day” to “night” early and make an unexpected appearance which increases their number. Later the stakes are raised by the ghosts summoning a rescue sub to the base using morse code.
The Doctor notices that the ghosts appear to be trying to say something. He wants to catch them and there’s a pretty exciting sequence with the ghosts chasing different members of the crew through the corridors until they are cornered in the faraday cage room.
There the doctor gets the lip-reading member of the crew to work out what the ghosts are saying. That clue leads him to recovering a life support pod that had been in the alien ship.
Towards the end of the episode the power fails and part of the base is flooded. The Doctor and Clara get cut off from each other. The Doctor decides to take the Tardis back in time to before the village was flooded to find out what happened with the alien ship and promises to come back for Clara.
As the Tardifs dematerialises Clara sees a new ghost appears outside the base. It is of course the Doctor. It’s a great cliff-hanger, although it is slightly reminiscent of the one from series 4 in the Library two-parter. You know, “Donna Nobel has been saved.” That one.
Still, this was a very entertaining and gripping episode. Capaldi is on good form as a Doctor that is fascinated that ghosts might actually exist. Clara has to remind him not to say inappropriate things by producing a set of prompt cards so he can read “sorry for your loss” unconvincingly.
As with most of the stories in series 9 this is a two-parter and works well for having the cliff-hanger and the continuing mystery of what happened in the village before the flood.