The next doctor: Christmas 1851, and Cybermen stalk Victorian London. The Doctor discovers a spate of mysterious deaths, and he's surprised to meet another Doctor. The two Doctors will need to be enough to stop the rise of the CyberKing. Planet of the dead: When a London bus takes a detour to an alien world, the Doctor must join forces with the extraordinary Lady Christina. But the mysterious planet holds terrifying secrets and time is running out...