Eighteen and now legally adults, Mary Ann Markham and best friend, Jennifer Martin, offer to help a high school friend find out who murdered her boyfriend at a nearby trout nursery. However, instead of quickly identifying the killer the girls are hounded by additional bodies that may or may not be victims of the same murderer. A surprise addition to their team from a local homeless shelter adds her expertise, and Mary Ann's adoptive parents, Art and Marsha Parker, get dragged into the investigation as usual. The girls get trapped in an abandoned warehouse, nearly get run over by a train, and are imprisoned in a walk-in refrigerator before finally stumbling on the solution, which almost results in their names being added to the growing list of corpses.