Gun runners named Roxanne Trent (Elizabeth Allen) and Commander Corliss (Robert Quarry) plan to kill Wilma as part of their revenge for her capturing them years earlier, during which their ship had caught fire and disfigured them both. Their plans involve the use of captured 20th century nerve gas, which is still potent enough to destroy all life on Earth. As commander of the Defense squadron, Wilma must find a way to locate and destroy the gas, which is hidden at the gun runner's hideout inside an asteroid belt. She discovers that the only one who has knowledge of how to traverse the belt is Major Noah Cooper {Peter Graves), an old friend of Wilma's father, and the elderly leader of a retired squadron, the Fighting 69th. Although the pilot is willing to lead his old pilots through the asteroids, Wilma does not know whether or not she should ask him, believing that the age of his squadron may be too great to complete the mission.