The story centers around a spirited high school girl named Marika. She keeps herself busy with the space yacht club and her part-time job at a high-class retro café. One day, two strangers suddenly appear and claim to be subordinates of her dead father. They demand that she assume command of the space pirate ship Bentenmaru. A privateer ship's compact was made during a war of independence a century ago, and according to that compact, the ship must be inherited by the captain's next direct descendant. Marika finds herself embarking on a new life as a space pirate.