After her husband passed away, Kaoru raised her son Tatsuo alone. Worried about the effects of their single-parent household, she wondered if Tatsuo's introverted nature would allow him to get along with his friends. One day, Tatsuo brought a classmate home—it was the first time he had ever done so, and Kaoru couldn't hide her joy. However, that joy was soon betrayed. It turned out that Tatsuo was being bullied by his classmates. And their malicious acts even reached Kaoru…
