Jack Mason of the Coast Guard Academy meets Mary at the graduation ball and falls in love with her, though the girl's mother finds wealthy Rex Cutting a more proper choice for her daughter. On a yachting cruise arranged by Mrs. Trumbull, Jack is not invited. Meanwhile, Mary suspects Rex of picking up contraband beyond the 12-mile limit and refuses his proposal of marriage, while Betty, her impish sister, drives Skippy to distraction in the galley, where he has installed an automatic kitchen that does most of his work. Jack smuggles himself aboard but is forcibly ejected at port by a coast guard, and Mrs. Trumbull discourages his attempt to elope with Mary; but on a subsequent cruise, he hides himself in a lifeboat with two aides. When the captain stops to take on a cargo of rum, Jack and his aides take over the vessel, and a battle ensues. The yacht is wrecked on an island, and Jack proves his heroism, while Rex reveals his true colors and is identified as a fugitive bootlegger.