The story of the film begins after the events of the second season, at the graduation ceremony of the third-year students. Knowing that the graduation of the third-year members means the end of μ’s, the nine girls take a walk around the school filled with memories. However, when the students attempt to leave the school gates, a single email is sent to them, and the curtain on a new story for μ’s begins.

The city is infested with mysterious parasites that bore into their human hosts to increase their host’s power and sexual desires. A beautiful girl, Suzune Arizono is a vet with a specialty in parasites, and who fights daily to end the plague. Before long, she learns that an evil organization, the Kito Zaibatsu, is behind the explosive growth of this ferocious parasite. She also learns that her long-missing father, Dr. Arizono, is also involved. In order to crush the Kito Zaibatsu’s ambition and to see her father again, Suzune takes on the fight without regard to the danger involved.

Set within a city where parasites rage, the parasites settled into their human hosts and increases their power and sexual desires. Dr. Suzune is a parasite expert who works daily to kill the parasites. A sinister demon organization exists behind the parasites. Dr. Suzune also realizes that her father, who went missing when she was a young child, is somehow connected with the group. Violence and madness awaits for her …