The G-man's son at Porpoise Island

Stanley Sandborn, the son of a federal agent, and his quick‑witted friend John Tallman set out on the sloop Water Witch for a weekend of sailing and camping around the remote Catlow Islands. Their plans take a sharp turn when a strange, gray speedboat slices through the wake, hinting at hidden activity near the forbidden Porpoise Island. Intrigued and a little uneasy, the boys steer toward Black Cove, a secluded harbor that Stanley’s father once marked on a chart as a perfect little inlet.

As they drop anchor, the quiet cove reveals clues that suggest the speedboat isn’t a harmless racer but part of something larger and more dangerous. With their youthful curiosity and a touch of their recent experience tracking gangsters, Stanley and John find themselves drawn into a puzzling mystery that could involve smuggling, secret plans, and the shadowy world their fathers police. The adventure blends nautical excitement with a teen’s sense of duty, setting the stage for a suspenseful chase across island waters.