Jonathan Osborne, the 14-year-old son of widow Anne Osborne, has become involved with a group of boys led by a neo-Nietzschean sadistic boy named "Chief". Anne daydreams about her husband who died three years earlier. When a large merchant ship anchors temporarily in the harbour, Anne arranges to give her son a tour of the vessel. They meet the second officer of the ship, Jim Cameron. Jim takes a liking to both the boy and his mother. Jim and Anne become involved sexually, which throws Jonathan into a rage of jealousy. Cameron returns to sea and while he is gone, Jonathan reveals his jealous sentiment to the group leader, Chief. When Cameron comes back to renew his relationship with Anne and forsake his life on the sea, Chief and the boys concoct a sinister plot to do away with the intruder.
