America, 1958. The Doctor makes a new friend, Cassie, who reveals that anyone approaching the top secret Dreamland army base goes missing. 

The Doctor discovers an alien army hatching beneath the New Mexico desert, while inside Dreamland, survivors of an extraterrestrial war possess a weapon powerful enough to destroy earth. 

While the Doctor and Saruba try to save the life of Rivesh, Cassie and Jimmy search for the TARDIS in the midst of a Viperox invasion.

With the Viperox invasion in full force, the Doctor needs the help of Rivesh Mantilax to activate the genetic device.