In a whimsical blend of space warfare and romance, the story follows Sakuya Igarashi, a high school student unexpectedly discovering her royal lineage within a star system. As threats loom from power-hungry bandits seeking to exploit her status, a surprising ally comes to her aid. Seven, a humanoid space battleship, assumes the role of an undercover protector at Sakuya's school to safeguard her from the looming political turmoil.