Three young monsters — Ickis, Oblina and Krumm — attends an institute for monsters under a city dump and learn to frighten humans.
Six years ago, the space alien ALF was on his way back to his new home when the Alien Task Force finally caught up with him. Now he is being studied at a top-secret base. There he finds allies who feel that ALF's existence should be announced to the world to ensure his safety... especially when they learn that the abrasive Colonel Milfoil wants ALF destroyed.
Thelma Harper and her spinster sister Fran open their home to Thelma's recently divorced son Vinton and his teenage son and daughter. It's quite an adjustment for everyone, especially the cranky, argumentative Thelma.
