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.

Marty and Debbie find out all the facts of alien love when Zabvronian mating season coincides with their wedding anniversary. Debbie longs for a little more romance in her marriage after she learns about the more cerebral Zabvronian way, while Jackie Joyner-Kersee is fascinated by humans' more physical approach. Meanwhile, a handsome jock invites Amber to a make-out party and she decides to go, with Reggie Jackson tagging along.