A young boy at his parents' coastal inn discovers a seafaring chest and a map to buried riches, then joins an expedition that sails to a remote island. The voyage and the island search reveal greed, deception, and divided loyalties as some crew members conspire to seize the treasure, while others work to keep order. Encounters include shipboard violence, a castaway's aid, and a fortified encampment, followed by skirmishes, cunning negotiations, and an eventual recovery of the hoard. The narrative alternates first-person recollection and other perspectives to blend adventure, suspense, and reflections on courage and betrayal.