Des Kinvig, owner of a backstreet electrical repair shop and part-time UFO nut, discovers that one of his customers, the beautiful but fiery Miss Griffin, is really an emissary from the Planet Mercury who has come to Earth to help prevent an invasion by the evil alien Xux... or is it all part of Des's fevered imagination?

Lazy repairman Des Kinvig's life changes when he imagines meeting a glamorous alien from Mercury, who looks a lot like his latest customer Miss Griffin.