While still becoming accustoned to his father's remarriage, thriteen-year-old Todd and a friend set out to prove they observed a burglary no one believes happened. They had gone on a canoeing trip and discovered two men acting funny on the other side of the lake. Todd and Kevin witnessed what appears to be a burgluary. When they returned home with the tale of robbery, no one believes them. Todd's dad and stepmom want to give the boys the benefit of the doubt, however the police are skeptical and the owner of the house rudely denies that anything is missing. Todd sets out to prove he is right. Todd and Kevin decide to gather evidence by taking pictures. They are determined to solve the puzzling crime on their own. Todd and Kevin poke around and uncover evidence of not only the burglary but also a slick travel-club scam. They overhear the burglars plan a murder. The boys follow the burglary and uncover three murders. The boys devise a plan to steal the burglars canoe from them so as to trap them on Sanctuary Island with the dead body. Todd's parents get worried when the boys are discovered missing and call the police. The police arrive just in time to save Todd and Kevin from becoming the burglars next victims. The police retrieve a body from the canoe and get medical help in time to save the man. Todd and Kevin save the day and become local heros.