Kenji, the second son of three brothers, had always been seen by his mother Natsuko as a low-maintenance child. However, one spring, his older brother started a job and moved out, while his younger brother entered a boarding school. His father began living separately due to work, leaving the house suddenly quiet and empty. Facing loneliness and a sense of loss, Natsuko began to change. Seeing his mother's condition, Kenji felt bitterness and emptiness inside, and driven to reclaim the maternal affection he had never fully possessed, he starts to take action. As the family bonds begin to unravel, the story unfolds around Kenji's choices and descent into forbidden desire.