Decker Brown and the Monster Club is about a nerdy group of friends who live in a small town and have to deal with normal small town occurrences like bullies and walking by themselves through the quiet and safe neighborhood at all hours. After finding out that his family might have to move out of town, Decker decides he wants to have an actual adventure, which comes in the form of exploring the dangerous, boarded-up cave that the adults warn them not to go into. As Decker ropes his friends into getting involved with his questionable scheme, weird things start happening.