Transfer student Mizuki is bullied mercilessly by her classmate. Nevertheless, she is always able to maintain her composure. Kirie, who is also bullied, becomes interested in Mizuki and longs for her. The two become close.

Feeling unhappy with his gun, Jigen is looking for the world’s best gunsmith. He finally finds out that Chiharu, who runs a watch shop, is the person he’s been seeking. Then, Jigen meets Oto, who comes to Chiharu’s shop looking for a gun. Jigen finds out about Oto's secrets and the mysterious organization that’s after her. After Oto is kidnapped, Jigen gets into a desperate battle to save her.