Exotic. Smart. Lethal. Musashi #9 doesn't live the life of a normal teenager. Her's is full of intrigue, violence, and death.

Some people want to change the world. This sixteen year-old girl can. Deep ideological, religious, and social differences drive the world closer to destruction, and the innocent masses suffer while politicians huddle in safety.
One ultra-secret organization is committed to preserving world peace, and their top agent goes by the code name Musashi #9. This agent battles terrorists and extremists, while bringing hope to the people she saves. The world may be a dangerous place, but it's a whole lot safer with Musashi #9 in it.

A series of unsolved murders have the entire neighborhood scared, when one night, middle schooler Majima Yuuichi observes two figures from his window, resembling his classmates Izumi Kiruto and Matsuda Ryuuji, near the most recent crime scene. Confusion turns to horror when Izumi turns into a monster, and though he tries to convince himself that this incident was only a dream, Majima cannot shake off his fear, and starts avoiding them.

Two years on, now in high school, Majima is horrified to find that he has ended up not only in the same school as the two popular boys, but also in the same class. But is there really more to the two wrestling-fanatical, somewhat idiotic new friends than it seems?