Kazuki is an exemplary student with a loving family and is working hard towards attending a prestigious private middle school. However, he starts experiencing unexplained stomach pains, leading to a rebellion of pent-up anger, pressure, and guilt in his heart. Kazuki is unable to find an outlet for these feelings and starts harassing and bullying his childhood friend Dosanari in dangerous ways.

One day, Aita appears before Kazuki, and with Aita's help, Kazuki finds himself in an abandoned house in the woods. Will Kazuki be able to overcome his inner turmoil and find a way to live happily again? "Kazuki" is a heart-wrenching novel about the struggles of youth and the power of friendship to heal the wounds of the soul.