Popeye receives a telegram that King Blozo is in trouble and goes to Spinachia with Olive to see if he can help him out. He discovers that Spinachia is under bombardment from nearby Missile City, a kingdom of living missiles. He takes a missile taxi with Olive and King Blozo to Missile City, where the Mad Missile Leader invites them on a tour of the city. When the Mad Missile discovers who they are, he puts them in prison and explains that they have only one can of spinach left which is kept in a safe, and that they are attacking Spinachia to get the necessary spinach. It contains iron, which missiles must have. Popeye gets the can from the safe, which was left open, and stops the invasion. He feeds some of the spinach to the dying Mad Missile, who quickly recovers. Popeye promises to teach the missiles how to grow their own spinach, and the Mad Missile promises that there will be no more invasions. Popeye, Olive and King Blozo leave Missile City as the missiles cheer.