The Time Lords have a mission for the Doctor. Together with Sarah and Harry, he finds himself stranded on the war-torn planet Skaro where the conflict between the Thals and the Kaleds has been raging for a thousand years. Chemical and biological weapons have started a cycle of mutation among the planet's inhabitants that cannot be stopped. But Kaled scientist Davros has perfected a life support system and travel machine for the creature he knows his race will ultimately evolve into - the Dalek. The Doctor must stop the creation of the Daleks, or perhaps affect their development so they evolve into less aggressive creatures. But with Davros's plans to destroy the Thals and to wipe out any dissenters among his own ranks in progress, is the Doctor already too late? This novel is based on a Doctor Who story which was originally broadcast from 8 March-12 April 1975. Featuring the Fourth Doctor as played by Tom Baker with his companions Sarah Jane Smith and Harry Sullivan