Following a mid-orbit collision between a space shuttle's satellite and a UFO, the US government secretly relocates the crashed spacecraft to a top-secret facility, Hangar 18, in Arizona. Driven by political optics and an upcoming election, ruthless White House staffer Gordon Cain orchestrates a massive cover-up, framing the surviving astronauts for the mission's disaster. The astronauts then go on a perilous quest to clear their names and expose the conspiracy.