During the reign of the Empire, a rabbit-like alien slave named Lop escapes her captors on the planet Tau and is discovered by the planet's clan leader Yasaburo and his daughter Ochö, the latter of whom convinces the former to adopt Lop as his daughter. Seven years later, the Empire has occupied their planet and is exploiting it for its natural resources; Yasaburo wants to drive the Empire off their planet, while Ochö wants to cooperate with the Empire. After failing to convince Yasaburo to join her, Ochō enlists in the Imperial navy despite Lop's protests...