YoungJonahJohnsonandhisfamilymoveintoMystic,CT.Thetown'slocalfisherman'sson,Schooner,quicklybefriendshimandthetwosoondiscoverwhatseemstobea300-year-oldtreasuremap.ThetreasureofCaptainKiddthatwaslostinthetown3decadesearlier.Whiletryingtoevadethetown'sbullies,JonahandSchoonerkeeptheireyeonCliveSteelway,arichtreasure-seekerwhoseemstohaveconnivingplansforthetreasureandtheboys.