The Aldens are visiting a small town known for its fall festival, and while Grandfather is off taking in the fall colors, the children try out the town's newest attraction—a Halloween escape room! The Aldens love solving the puzzles to get out of the room, and they don't mind the spooky theme. The problem is, someone—or something—is making things downright scary for other customers!

Jessie wants her science fair project to make a difference. So when she gets the chance to test a local creek for pollution, she can't wait to get started. But when things start going wrong with her experiment, Jessie and her siblings don't just have an experiment to investigate, they have a mystery to solve!