Gordon Shumway is an alien from the planet Melmac who follows an amateur radio signal to Earth and crash-lands into the garage of the Tanners, a suburban middle-class family who live in the San Fernando Valley area of California. The family consists of social worker Willie (Max Wright), his wife Kate (Anne Schedeen), their teenage daughter Lynn (Andrea Elson), younger son Brian (Benji Gregory) and their pet cat Lucky (whom Gordon wishes to consume). Gordon is given the nickname ALF ("Alien Life Form") by Willie Tanner.