A woman is cheating on her wealthy husband with a "beach bum". He knows about the affair and is suing her for divorce. Before the divorce goes through and she loses all the money, she and the beach bum plot to kill him. The beach Bum also has a personal grudge against the sea boat captain. It is on his ship that the rich husband and his friends travel, gamble, drink, and get away regularly. The plot: kill two birds with one bomb.