The narrative follows three young friends whose motor boat is wrecked in freight transport shortly after a Florida cruise; refusing defeat, they set out across the continent to the Pacific coast to search for a mysterious derelict. Joined by an eccentric professor and later equipped with a powerful motor craft, they face fog, storms, rocky shoals, rival searchers, and an embittered antagonist whose machinations lead to a climactic confrontation. Along the way they experience narrow escapes, coastal encounters with a hotel family, a side quest involving a horned toad, and ultimately discover and resolve the mystery of the derelict.