In The Underwater War, the Eleventh Doctor and his companions are on board the Cosmic Rover, a spaceship orbiting the water planet Hydron. Joining the crew, they journey underwater on an apparently scientific exploration. But nothing is as it seems on the high-tech submarine. When a virus infects the crew, the Doctor discovers the ship is hiding a dangerous secret . . .

Richard Dinnick is a screenwriter, novelist, comic writer and audio playwright. He has written for the BBC, including on Doctor Who, and was a BAFTA Judge in 2014.