Gordon Shumway, last known survivor from the planet Melmac, crash-lands his spaceship into the Tanner family's suburban garage. Willie dubs him "ALF", short for Alien Life Form. After convincing a military officer that they are not harboring a space creature, the Tanners decide to take ALF in as a member of the family.

Willie helps homesick ALF arrange a trip to Melmac.

The Tanners are invited to a Thanksgiving dinner with the Ochmonek's bizarre relatives.

ALF must avoid the Alien Task Force when a bum blows the whistle on him.