The TARDIS lands on the jungle planet Spiridon, where the Doctor has fallen into a coma, where The Doctor has requested the Time Lords to pilot the TARDIS, so he and Jo can follow the Daleks to their base. Where Jo learns the Dalek's base has been located on Spiridon where the Daleks are attempting to discover the secrets of Invisibilty and create a bacterial virus in their goal of universal conquest. Where The Doctor, recovered from his coma and Jo are joined by a task-force of Thals and a native Spiridon named Wester, Where they not only set out to stop The Daleks evil plot, they also discover a army of 12,000 Daleks are in suspended animation and are waiting to be revived to begin their universal conquest and claim themselves as the supreme rulers of the galaxy.

The Doctor and Codal escape from their cell and meet up with the Thal commandos who are trying to get into the Dalek base.