The Great Healer works in the catacombs beneath Tranquil Repose, the galactically-famous final resting place for the dead and the not-quite-yet-dead. In the upper chambers the busy workers prepare the deceased for their final burial, while deep below the Great Healer is using their bodies for a sinister project of his own. For the Great Healer is also known by another name - Davros, creator of the Daleks, who's using the bodies to build himself a brand new Dalek army. The Doctor must quickly act to stop Davros, but the evil scientist has a plan that will eradicate all opposition and enable him to lead his Daleks on a new mission of universal conquest...