Yoshifumi Nitta, a yakuza member, stumbles upon a mysterious capsule containing a powerful blue-haired girl named Hina. To prevent her powers from causing chaos, Nitta reluctantly becomes her caretaker. When a rival yakuza group frames him for an attack, Nitta enlists Hina's help in a dangerous mission. Surprisingly, Hina displays her strength by aiding Nitta in defeating their enemies. This unexpected partnership sets the stage for a unique and unpredictable journey as they navigate the complexities of the yakuza world together.