Twenty years after her husband dies in an accident, Maki and her adult son Yuta live comfortably on the insurance money. Yet one troubling habit remains: he was never weaned from her breasts. His father's death traumatized him as a child, and he sought comfort by nursing whenever he felt distressed. Worried about his future, Maki finally tells him it must stop. Yuta asks for just one final week and promises he will quit afterward, pushing this taboo adult mother-and-son role-play toward an intimate turning point.