The Doctor runs afoul of the Daleks and Special Security Agent Bret Vyon on the planet Kembel.

The Doctor infiltrates the Daleks' conference to try and discover their plans, leaving Steven, Katarina and Bret to find a way off the planet.

The Doctor and his friends escape Kembel in the Spar ship but the Daleks force them down on the planet Desperus, where they are threatened by a group of convicts.

With Katarina being held hostage, the Doctor, Steven and Bret are in danger of having to given in to Kirksen's demands, while, on Earth, Chen has them listed as traitors.