Tsukasa Atsumi is a salaryman who lives an ordinary, solitary life in the busy city. After a long day at work one evening, he is rescued from a demon attack by an enigmatic woman dressed in ninja attire. She introduces herself as Shizuri Ideura and tells him that demons target people with Samurai Blood, like Tsukasa, and that her clan has been protecting such individuals from the shadows.
Shizuri warns Tsukasa that attacks will become more frequent, and he agrees to provide her with a place to stay in exchange for safety. To his surprise, he learns that she is a shut‑in who loves playing video games whenever she isn"t busy with her ninja duties. And she smiles. As they spend more time together, Tsukasa grows to appreciate Shizuri"s company—and his feelings might very well be mutual.
