Nanoha Kido, who works as a programmer at an IT company, has a natural enemy. His name is Mr. Haba, the cold-hearted boss! He's a disgusting boss who seems like a nice guy, but always pushes impossible tasks onto Nanoha. One night, after working overtime due to work given to her by Mr. Haba, Nanoha enters a live music venue that she visited during her student days. There, Nanoha saw the unexpected appearance of a band member she was once a fan of...!?