Barnes, the mate of the 'Portland', is the object of the hate of the whole ship's crew. His mistress is murdered shortly before the departure and suspicion naturally falls on him. Some time later, Jeff Cooper, the skipper, falls to his death in the middle of the night. Once again Barnes is suspected and the mate has to resort to force to maintain his authority on board. During the stopover, Barnes is interrogated and finally cleared. He is even appointed captain of the 'Portland' in replacement of Jeff and can marry his best friend's daughter.