The astronauts Gary Collins, Steve Bancroft, Lew Price, and Judd Gates are responsible for releasing a satellite to Mars from a space shuttle. Out of the blue, the capsule hits a UFO and Gates is beheaded. An UFO crashes on the soil of Arizona and is immediately sent to Hangar 18 in a top secret mission by the politician Gordon Cain, who is responsible for the reelection of the president of the United States. He discusses the case with his assessor Frank Lafferty and with a military chief, and resolves to blame the astronauts for the death of Gates to keep the ratings in the reelection of the president. However, the two astronauts are resolved to find the truth. They travel to Arizona, but they are hunted down by Gordon Cain's men.