Fifteen-year-old Pete Jenkins and his three summer friends return to their cottages following a perilous escapade on nearby Mackinac Island. They soon learn that many boathouses in the Les Cheneaux Islands resort community are being looted - theirs included. Curiosity prevails and the teens investigate. Their sleuthing adventures are frequently interrupted by a wonderful array of social activities - fishing, partying, and participating in a benefit basketball game. Unknown to them, however, the escaped Mackinac murderer lurks in the shadows plotting a fiendish scheme of revenge!