John Croxley's talent for extra sensory perception is heightened after his wife is killed when a UFO crashes into their house. With his mind under the influence of the Aliens, Croxley learns the secrets of SHADO and lures Straker and Freeman to the remains of his house - to kill them!

Suspecting a UFO to be responsible for the sinking of a freighter, Straker, Foster and Nina Barry investigate in Skydiver. Attacked by an undersea UFO, the submarine is downed on a ledge on the sea bed and the crew are trapped. While Straker fights against his claustrophobia, Nina faces a living nightmare...