The Doctor and Sarah arrive safely back on Earth - or do they? Why does the mysterious soldier march straight over a cliff — and then reappear unharmed?
Why are they attacked by the sinister mechanics with built-in guns for hands? Why is a picturesque country village at first deserted — then filled with mindless zombies?
And why are their best friends suddenly trying to kill them? The Doctor has stumbled on a cunning alien plan to take over the Earth. Will he be in time to defeat the deadly Kr...