A married couple, Shihori and Ken, live an ordinary family life with their son. Despite having a child, their love for each other remains strong—growing ever deeper and more intense. While their son is surrounded daily by his parents' warmth and affection, he gradually begins to feel a strange unease and curiosity toward his mother. These emotions slowly transform into sexual longing. One night, the son secretly watches his parents' intimate moments, and as jealousy and desire intertwine, he resolves to keep a secret of his own. A story unfolds where familial warmth crosses paths with forbidden passion.