Olive has a map to a sunken treasure, but Bluto stowed away and is determined to beat Popeye to it. First, he sees to it that Popeye gets stuck inside a giant clam. Next, he jams a swordfish into the ship's figurehead, creating a mermaid that Popeye falls for, until the swordfish has enough and saws his way out. A quick firing of a cannon sends Popeye to the surface briefly. He comes back down just as Bluto has finally extracted the safe, and Popeye walks off with it. Bluto gets it back, and gets Popeye tangled up with an octopus as he sails off with Olive and the safe. Popeye eats his spinach and rows after them on the carcass of the sunken ship, then dispatches Bluto. Olive opens the safe, and faints at the contents: a movie star photo.