Plot

Paul Foster and his co-pilot Frank Craig are attacked by a UFO which infiltrates their minds and hypnotises them into wanting to kill Straker. Straker actually saves their lives when their craft is about to be destroyed, but, on their return to SHADO, Craig makes an attempt on Straker's life whilst Foster seeks to discredit him.—don @ minifie-1

A UFO gets through the moonbase defense zone and intercepts a lunar module on Earth reentry. The two-main crew is brain-washed by the aliens and given a simple objective: kill Straker. While one crewman takes the direct approach, Colonel Foster starts to undermine Straker's authority and challenge his leadership of S.H.A.D.O. - establishing an alibi and leading up to his own attempt on Straker's life.