Three astronauts who were lost in space finally return to Earth, only to find that during their absence the planet has been ravaged by nuclear war, and is rife with radiation. In order to survive, the trio must fight for survival amongst flesh-eating mutants, gun-crazy maniacs, and other unsavory, demented types. Meanwhile, a teenager who runs his own slave trade operation is becoming drunk with power. The space travelers must use their survival instincts to defeat the egomaniacal teen.