It is the year 2025, five years since devastating terrorist attacks put an end to the 2020 Tokyo Olympic Games. The UN has taken control of the former Olympic site on the edge of Tokyo Bay, placing it beyond Japan’s jurisdiction.
Hana Togetsu is a seventeen-year-old high school student who lives in the area. Not your typical teen, she belongs to a special unit run by the UN. Hana is sent on a mission as a transfer student to a public high school on Enoshima Island.
Her target: Shunichi Nanase, a boy in her class.
As Hana is about to make contact with her target, a middle-aged man appears at the school asking for Shunichi. The situation turns critical when the American military arrives at the school in pursuit of the man.
As the bloodshed escalates, another teenage girl begins to make her way to the island to break the deadlock.