Straker believes that orbiting space junk is a hazard to SHADO operations, and demands that General Henderson fund a program to eliminate it. A SHADO lunar module is then destroyed during Earth reentry by an Alien device which steepens the module's reentry flightpath angle. However, Henderson is convinced that the accident was pilot error, and puts a ban on all lunar flights. Col. Foster violates the ban to prove that the accident was not pilot error. He survives his encounter with the Alien device by starting at a very shallow reentry angle. Straker then orders all three Interceptors to destroy suspected pieces of space junk which an Alien device may be hiding in. However, while the Earth is left undefended, a UFO is sighted and its target is SHADO headquarters!