The solitary survivor of World War III and a subsequent alien invasion embarks on a quest to restore the balance of nature and make the world livable again while battling evil aliens, crazed survivors, and faulty equipment that fails him at every turn. Upon awakening from an extended cryogenic slumber, John Glass is horrified to find the entire planet in ruins. As if mankind couldn't destroy himself well enough alone, a massive alien invasion has rendered most of Earth completely uninhabitable. But there's still hope; if John can just locate a series of secret codes, humanity could rise once again - perhaps even stronger than ever before. Unfortunately for John, the codes are well hidden, and the few remaining creatures on the planet are just itching for a fight.