Captain Biff Brown owns a boat used to ferry prisoners from the mainland to Alcatraz. The police find some escape tools on his boat and, although Brown isn't involved, his contract is terminated and he goes back to tuna fishing. Brown takes his friend Sanderson to his boarding house and introduces him to his sweetheart Madge Harris and Sanderson also falls in love with her. A gang headed by Red Mason and trying to escape the country bribe Brown's engineer, Venatti, and are hiding on the boat the next time Brown and Sanderson take it out.