Shinichi Masaki, an ordinary high school student, becomes entangled in an intergalactic adventure after a chance encounter with a space pirate. While delivering lunch to his cousin Tenchi Masaki, Shinichi is accidentally transported aboard a spaceship belonging to the Galaxy Police (GP). Despite his initial reluctance, he is recruited into the GP due to a unique ability to attract misfortune, which the organization believes can be used to their advantage. Shinichi is assigned to the Special Duty Section, where he is tasked with handling dangerous missions across the galaxy.

Shinichi’s life takes a dramatic turn as he is thrust into a world of advanced technology, alien cultures, and interstellar politics. He is given command of a custom-built ship, the Kamidake II, and gradually builds a crew consisting of diverse characters, including Amane Kaunaq, a skilled pilot and former pirate; Kiriko Masaki, his childhood friend and GP officer; and Ryoko Balta, a mysterious and powerful woman with ties to the Juraian royal family. As Shinichi navigates his new role, he faces numerous challenges, including hostile alien factions, bureaucratic obstacles within the GP, and the complexities of his growing relationships with the women around him.

The series explores themes of duty, camaraderie, and personal growth as Shinichi adapts to his new life. His journey is marked by a series of comedic and action-packed episodes, blending space opera with harem elements. The narrative also ties into the broader "Tenchi Muyo!" universe, with recurring references to characters and events from the franchise. Despite his initial ineptitude, Shinichi’s resilience and determination earn him the respect of his peers and allies, solidifying his place as a key figure in the GP’s efforts to maintain peace across the galaxy. The story balances episodic adventures with overarching plotlines, culminating in a climactic confrontation that tests Shinichi’s resolve and the strength of his bonds with his crew.