It's October in Gold Rush country and all manner of tricks and treats are happening in the lead-up to Halloween. October also happens to be the birthday of Angus Sprockles, the man responsible for the town being designated a historic landmark, and the residents are celebrating his memory as well. His only living descendant, Moses Sprockles, runs the narrow-gauge railroad—once used to ferry lumber from the mountains to the sawmill, now a tourist attraction. The Sprockles Railroad is hosting a Halloween-themed fundraiser for the Historical Society.

But when a body is found on the tracks, it's not a Halloween prank. It's Moses himself, seemingly felled by a fallen tree branch. Dee's dad Sam is convinced his friend is the victim of foul play and urges his daughter to apply her sleuthing skills. Dee's train of thought leads her to suspects ranging from a former child star and one-hit wonder, the owner of a nail salon with her claws in everything, and even the mayor. When a self-proclaimed ghost hunter throws his hat in the ring and claims to know who did it, the investigation really goes off the rails. No matter how crazy things get, Dee is determined to blow the whistle on a runaway killer with a one-track mind.