There is a dark, haunted mansion in which the strange reclusive Franklin Lyle (Ernest Borgnine) lives. Suspense builds as the kids meet slick Jimmy Murano (Jason Hervey) and his devious lawyer, Camile, who are trying to force Franklin off the property. They will succeed if they solve a decades-old mystery, and find a hidden treasure before anyone else. Suspense and humor abound as we follow the group’s escapades including a car chawse and a hurried attempt by Sheriff Burke(Cris Borgnine) to auction the old mansion out from under Franklin. The day is saved with the treasure discovereed, the mansion saved, romance renewed, and the crooks thwarted. Not too bad for a lame summer vacation at Grandma’s.