Don't you forget this! I'll never forgive you!

When Kusano Naho, Hirao's childhood friend, was in her sixth year of elementary school, her father apprehended two fraudsters. Hirao, who happened to witness the fraudsters being escorted away, became concerned that the men might harm Naho after their release from prison. After much agonizing, he decided to train himself at a dojo on the outskirts of town to be prepared for that day. However, Naho found Hirao, who had started spending all his time at the suspicious dojo, unsettling and began to distance herself from him.

Even if Naho disliked him, it would be enough if she could enjoy her everyday life.

Until that day came, Hirao dedicated his entire life to protecting Naho.

And then, one day during his second year of high school...

Also posted on Kakuyomu.