After her husband passed away, Hitomi Honda raised her son alone. Now that he’s graduated and has a job lined up, he asks for her body as a graduation gift. Thinking it was a joke at first, she eventually gives in to a one-night stand. Later, her son’s workplace relocates far away, so they go on a hot springs trip together. Hitomi longs to hold her son again, and their forbidden incestuous love blossoms. Despite knowing it’s wrong, she loses her composure at her son’s earnest gaze. They engage in forbidden necrophilic activities, licking each other’s genitals and having sex repeatedly during their hot springs trip.