Somewhere in outer space, the megalomaniacal General Suitor attacks a planet and holds its leader, President Hashina, hostage. Intergalactic warrior Shep Ramsey destroys Suitor’s mother ship, but is unable to save President Hashina. Zanuck, Shep’s commander, considers this failure to be the result of overwork and orders the warrior to dock at the nearest planet to “recharge” for six weeks. Shep obeys the order and heads for Earth, despite his aversion to its inhabitants. In Van Nuys, California, architect Charlie Wilcox is advised by his wife, Jenny, to demand a pay raise from his unappreciative boss, Adrian Belz. However, Adrian anticipates Charlie’s request and distracts him with token praise for his hard work and dedication. Adrian shows Charlie the company’s collection of crystalline trophies, assuring the architect that they are more valuable than money. Meanwhile, Shep lands in an abandoned Van Nuys nightclub and charges his spacecraft with a high-voltage cable. On the street, Shep’s exotic uniform and muscular physique attract attention as he performs random good deeds. He notices a leaflet, posted by Jenny Wilcox, advertising an apartment for rent and makes his way there. Charlie arrives home from a frustrating day and seeks refuge in his backyard workshop, but is infuriated to discover that it has been converted to an apartment, and rented to Shep. Later, while Shep is out, Charlie searches the apartment and finds a gun that fires a destructive ray. Although Charlie is uncomfortable with Shep’s presence, he is too intimidated by the warrior to ask him to leave. The following afternoon, Shep saves Charlie’s son, Mark Wilcox, from being struck by a car, and Jenny shows her gratitude by inviting Shep to dinner. Afterward, Shep walks to the abandoned nightclub, unaware that Charlie is following him. When Charlie is alone in the building, he discovers a robotic suit of armor, which he dons to defend a girl who is being molested by two “punks.” After rescuing the girl, Charlie accidentally leaves behind a gun that temporarily freezes its targets. Meanwhile, the armor sends a signal into space that guides General Suitor’s bounty hunters, Knuckles and Teeth, to Van Nuys. In the morning, Shep learns of the bounty hunters’ approach and notices his freeze gun is missing. Using a tracking device, he and Charlie locate the gun at a bank, where all of the customers and employees are frozen while the two punks rob the vault. Shep wrests the gun from the robbers and subdues them, but not before Charlie is frozen. When the bounty hunters arrive on the scene, Shep makes a narrow escape and takes Charlie back to the nightclub to thaw. As Shep readies his ship for departure, a power surge damages the engine, which can only be repaired with forty pounds of crystal. Charlie suggests using Adrian Belz’s trophy collection, and takes Shep to the office building, where a cocktail party is underway. Adrian’s secretary, Margie Tanen, takes an immediate liking to Shep, but he cannot be distracted from his mission. As he and Charlie make their way to Adrian’s private offices, Shep laments his lack of a personal life because so many planets need saving. As Charlie and Shep gather the trophies into a bag, Margie holds them at gunpoint, demanding the items be returned. The bounty hunters land on the roof and confront Shep, while Charlie and Margie take cover. After considerable damage to the building, Shep dispatches his adversaries and prepares to leave Earth, believing his presence may endanger the planet. Charlie returns home to find his family held hostage by General Suitor, who forces the architect to lead him to Shep. Suitor demands Shep’s surrender, or he will kill the Wilcox family. Shep activates the self-destruct mechanism in his spacecraft, then promises to surrender if the earthlings are set free. Suitor complies, but as the family escapes, Charlie is unable to abandon Shep and goes to his aid. As Shep is struck by gunfire, Charlie dons the robotic arm and crushes Suitor’s genitals. Suitor transforms into a monster and knocks Charlie unconscious, and Shep electrocutes the general with a high-voltage cable. Seconds before his spaceship explodes, Shep carries Charlie to safety, and tells Jenny that her husband single-handedly defeated General Suitor. Jenny is proud of Charlie, but promises to kill him if he ever tries anything like that again. In the morning, Charlie quits his job, believing he deserves more money and respect from his employer. His family gathers on the roof of the Belz building as Shep departs in the bounty hunters’ ship, accompanied by Margie Tanen. As they say goodbye, Charlie jokes that he may become an intergalactic warrior, while Shep jokes that he may become a family man. Later, Charlie drives to work and wins the admiration of his fellow commuters by shooting an inconveniently placed traffic light.