The Eleventh Doctor and Amy help the SS Lucy Gray return home to Earth, unravel a Cyber Plot and prevent the Daleks from retrieving a lost Time Axis along the way. The Doctor and Amy arrive on a human colony ship on its way to Earth after the planet has been rendered uninhabitable by solar flares. They are attacked without provocation by the ship’s maintenance robots and become separated in the struggle. The Doctor is eventually led to the ship’s Headquarters. He discovers a Cyber Leader has connected himself to the ship's AI and is blackmailing it into doing his bidding, lest he kill the crew.