Disoriented after his regeneration, the Doctor takes the TARDIS to the Earth colony Vulcan. Ben and Polly are disturbed — the Doctor isn't the man he used to be.

The Doctor too is worried. The colonists have found the remains of two Daleks - which they plan to revive.

Once revived, the Daleks claim that they are content to serve humanity. Can it really be true? Or do they have their own, more sinister plans?