Kurogane Yuto, a third-year student living in Tokyo. He was never able to become a band bearer due to a rare degenerative illness. A constant battle where his body had to regenerate faster than it was being destroyed, using mana.

Ever since the disease manifested, he began to dream of strange people, night after night. And in every dream, it always ended with them being swallowed by a mysterious darkness.

After suffering bullying throughout his school life, he found refuge when Mizumi Sensei arrived. A teacher who, unlike everyone else, reached out her hand and welcomed him.

Inevitably, Yuto fell in love with his savior.

A powerful enemy appears, and Kurogane awakens his bands. Mizumi Sensei is taken, and a mysterious white-haired girl reveals that she knows the truth behind the darkness in his dreams.

What will Kurogane do?