The TARDIS arrives on the asteroid Livonia, where plans are underway for peace talks between the human-descended Zantha Empire and Tibari Republic (whose citizens are of piscine descent). A renegade Tibari scientist, Atrekar, kidnaps the Doctor, Zoe and Jamie; he has identified the Doctor and Zoe's intelligence, and decides to use them in his mind projector machine. The projector, which uses Dalek technology, creates a duplicate of Zoe, controlled by her intelligence via quantum entanglement, but subject to Atrekar's telepathic command. Atrekar has allied himself with the Daleks, and plans to use Zoe to assassinate the Tibari President and thwart the peace talks. The Daleks, for their part, are planning to use Atrekar's mind projector to conquer the galaxy.