Bonnie Montgomery decides to take a break from her criminal investigations as her alter ego Montgomery Bonbon, a brilliant detective. So his elegant beret, tattered raincoat and dashing mustache are safely hidden, and Bonnie herself, together with Grandpa Banks, goes to a resort town on the island. The sea breeze, martinis, colorful beach houses and the oldest lighthouse with a clockwork mechanism are a real delight for tourists. However, one after another, accidents occur in the town, so Bonnie still has to get out her detective mustache and get to work. After all, detectives are drawn to mysteries - like, you know, brand new rubber boots to a huge dirty puddle.