Watashi no Kizu wa Shinde mo Kesanai

A boy named Yamaneko Nokishita has two childhood friends: an older college woman with a scar on her forehead, to whom he promised lifelong responsibility, and a small-statured classmate named Mameshiba. The three occasionally spent time together, but when Yamaneko enters his final year of high school, a significant event occurs after he visits Mameshiba's home.