Ensign Thomas Garland takes command of a busy harbor in Newport Beach, California. Although senior officer Commander Taylor is eager to have the son of an illustrious World War II hero under him, enthusiasm wanes upon discovery of the officer's incompetence. After introducing himself to rental operator Kate Fairchild by spilling yellow paint over her, Garland attempts to rescue a rowboat, in the process grounding his Coast Guard cutter. As three thieves, Harry, Max, and Charlie, escape through the fogbound harbor, they collide with Garland's vessel. The jewels, hidden in a picnic basket, sink to the ocean floor. To recover the basket the trio recruits a voluptuous Japanese pearl diver, thereby exciting the ensign's suspicion. Informed of these events by Garland, Taylor is incredulous until Moby Dick, Kate's pet pelican, pilfers a jewel-encrusted pickle. During the thieves' flight by submarine and seaplane the jewels are jettisoned. Garland recovers the cache, selecting from it an engagement ring for Kate.