Kenji, the second son of a three-brother family, was always the low-maintenance child in the eyes of his mother, Honami. But one spring, everything changed—his older brother moved out after landing a job, his younger brother entered a boarding school, and his father began living separately due to work. Suddenly, the house fell silent. Overcome with loneliness and a sense of loss, Honami struggled with the emptiness. Meanwhile, Kenji, long overlooked amidst his siblings, began to feel the absence of affection directed toward him. Seeking to draw his mother's attention and emotional warmth, he gradually steered her feelings toward himself. As mother and son settled into their new life of cohabitation, the story unfolds the intimate and forbidden deepening of their bond.