John Moore (Reed Howes), a young sea captain has a romance with Kay Wheeler (Molly O'Day), daughter of a trusted trader, "Pop" Wheeler (A.S. 'Pop' Byron), on a Pacific island. He also acquire the enmity of "Shanghai" Morgan (Wheeler Oakman), a notorious sea captain who shanghais his crew and his women. Back in San Francisco, Morgan seduces and kidnaps Moore's sister, Mary (June Marlowe),who escapes but dies from the shock. Moore sails out for revenge and follows Morgan to his sweetheart's island.