The whole world is watching the first manned flight to Mars, but its three astronauts are plunged into a hair-raising battle for survival within a clandestine operation involving intrigue and murder.

The astronauts are removed from their spacecraft to an abandoned desert hangar and ordered to participate in an elaborate charade, simulating a Martian landing as cameras roll and with the entire world as an audience. On a nearby sound stage, a simulated walk on Mars is set. As the flight apparently proceeds on schedule, a NASA technician notices a discrepancy in a computer read-out. Receiving no co-operation from his supervisors, he casually mentions the incident to his friend, reporter Robert Caulfield (Elliott Gould).

Intrigued by the possibility of a government cover-up. Caulfield and a colleague search for the truth. After news reaches the captive astronauts that their rocket disintegrated upon re-entry and the world believes them dead, they know their very existence poses a threat to national security. The three astronauts escape and separate, hoping that one of them will live to expose the sensational fraud...