A divorced mother who has been raising her son alone since he was young feels lonely when he graduates and moves to Tokyo for his job this spring. She can't help but worry that he might leave her side forever... Out of gratitude, she decides to join him on a graduation trip just for the two of them. As they soak in a hot spring together, their long-repressed desires take over, and they give in to their forbidden lust for each other. This taboo story unfolds as mother and son surrender to their primal instincts, losing themselves in passionate acts of incest. Note: The content may vary depending on the distribution method.