Feeling guilty because he has lost fifty thousand dollars of her money on a stock deal, Paul Herrick doesn't want to marry multi-millionairess Jane Lansing. She insists, though, so he takes the ferry to her Marin County estate. Drunk, he falls off the ferry in the fog and is saved by the Romandi family, who think that he tried to commit suicide. They take him in to recuperate and, thinking that he is down on his luck, offer him a job fishing on their boat. He is impressed with the warmth of the family, as well as their daughter Angelina, so he decides to stay for a while. The first day out, he wants to quit because the work is so hard, but Angelina encourages him to keep at it. Meanwhile, her father, Pietro is trying to keep racketeer Tony from forcing him to pay protection money. Several weeks later, Jane receives a report from a detective she has hired to find Paul and becomes jealous of Angelina, even though Angelina plans to marry community leader Mario after he pays for her singing lessons in Milan. When Mario learns about Tony's "protection" ploy against the Romandis, he advises Tony to stay away from them and slugs him to make his point. That same night, the family learns that their son Guido plans to turn down the Rhodes scholarship he has just won to remain with his girlfriend Marge, and Angelina tells them that she won't go to Milan and marry Mario because of her feelings for Paul. The oldest son, Benvenuto, is bitter against Paul and they fight on the boat the next day, but after Paul saves Benvenuto from drowning Paul decides that he should leave. On shore, Jane is waiting for him with a phony warrant so Paul decides to use it as a way to leave the Romandis without hurting them. Soon Marge, who has married Guido, tells Benvenuto that she is planning to leave him so that he can take the scholarship and be happy. Some time later, Angelina and Mario board the steamship Rosalina for Milan just as Paul and Jane board her yacht. That night, while Jane's yacht is being repaired, they hear that the Rosalina is on fire a short distance from them. Paul borrows a tug boat and rushes with his friends to help rescue the passengers. The fire, which started with a bomb delivered to Mario by Tony, looks fatal from a distance, but Paul manages to get aboard and rescue Angelina and Mario. Jane then invites the Romandis to her home in Marin County and she, Mario and Benvenuto convince him that he is a "rat" not to marry Angelina.
