The Doctor is still trapped on Earth and unable to use the TARDIS, but the Time Lords are looking out for him. They send warning that the Master has come to Earth and the Doctor soon discovers that the dangerous Time Lord is also working alongside the Nestene Consciousness, controller of lethal Autons creatures Once again, the planet is in terrible danger. Can the Doctor and new assistant Jo Grant save it before it's too late and the true terror of the Autons is revealed?