Shin'ya Miho is a model student who has spent his entire life suppressing his emotions. After losing his mother at a young age, he was raised by a rigid and domineering father whose strict expectations left no room for self-expression. Shin'ya learned to wear a mask of obedience, performing the role of the perfect son while burying any feelings that might displease his father. His world is one of quiet isolation and emotional numbness, where even his innocent crush on classmate Mayu Kawasaki feels hopeless from the start.

One day, while walking home, Shin'ya spots Mayu and, acting on a sudden impulse, secretly photographs her without her knowledge. This single act of voyeurism shatters the carefully controlled image he has maintained, forcing him to confront a dark and unfamiliar surge of desire. Overcome with shame and self-disgust, he retreats to a nearby park, where Mayu unexpectedly approaches him. Instead of confronting him about the act, she engages him in friendly conversation, revealing that she has been interested in him for some time. A moment of shared tension and vulnerability leads to the two confessing their feelings for one another, and they begin a secret romantic relationship.

Their bond brings Shin'ya a kind of happiness he has never known, but it is built on a dangerous foundation. He cannot bring himself to admit his crime to Mayu, terrified that she will reject him if she learns the truth. At the same time, he lives in constant fear that his father will discover the relationship and harm both Mayu and the fragile freedom he has only just begun to taste. The narrative follows the couple as they navigate their precarious bond, with Shin'ya torn between genuine affection and the weight of his hidden guilt. As the story unfolds, a series of escalating pressures, including a classmate's suicide attempt and the ever-present threat of discovery by parental authority, gradually pull Shin'ya toward a breaking point. The manga's opening scene, which shows a bloodied Shin'ya standing over a body, foreshadows that his repressed negative emotions will eventually erupt in violence, pulling both him and those around him into a spiral of destruction.