On Skaro, the home world of the Daleks, the Doctor encounters the militaristic Movellanswho have come to Skaro on a secret missionwhilst his companion Romana falls into the hands of the Daleks themselves. It soon becomes apparent that the Daleks have returned to their abandoned home city with a crucial objective, one which they hope will give them the advantage in a strategic war. When the Doctor realizes what the Daleks are up to, he is compelled to intervene. But he has not bargained for the Movellans having a few secrets of their own, and soon he, Romana, and the human refugee Tyssan are wondering who exactly they can trust. Moreover, will they be able to divert the Daleks from their self-proclaimed destiny?