Despondent over the infidelity of his wife, William McCabe wanders on the waterfront considering suicide, but instead he saves the life of Shark Moran. Moran gives McCabe a job on his lightship, where McCabe enjoys the solitude and falls in love with Ann Reynolds, the daughter of the captain of the supply ship. One day Moran rescues a woman in a storm and makes advances toward her. When McCabe discovers the woman to be his own wife, there is a violent quarrel between the two men. But their friendship prevails, Moran apologizes, and Helda McCabe reveals that William is free to marry Ann.