Marty and Debbie decide to make plans with their human friends after Larry and Jackie have become too entangled in their daily lives. The Weavers do their best to un-invite the Bird-Kersees, explaining they're afraid their friends won't be accepting of the aliens. But that doesn't stop Larry and Jackie from crashing Marty's' poker night and Debbie's girls' night on the town -- with hilarious results.

Since arriving on Earth, the aliens - led by the Bird-Kersees - have viewed Halloween as a threat and have set up a barrier at the gates of Hidden Hills to prevent children dressed in costumes from entering the community. The Weavers, on the other hand, are excited about their first Halloween in the suburbs and want to open the gates of the community to celebrate. They do their best to explain the ritual of trick-or-treating to the aliens. Meanwhile, Marty and Debbie's fears are realized when Amber, Max and Abby reject their family costume plans.