Former swimming coach Hatanaka and his protégé Makoto had built a deep bond through their club activities. However, six months prior, Hatanaka was expelled from his position as a coach under disciplinary dismissal. Despite this, Makoto continued to revere him, unable to let go of his desire for guidance, eventually forcing his way into Hatanaka's home to receive private training. But Hatanaka, lost and tormented by his daily struggles, had fallen under the grip of a twisted psyche. Under the guise of physical training, his instruction gradually turned lewd and perverse. Makoto, rather than resisting, found pleasure in the acts, embracing her masochistic side and undergoing a transformation into a new version of herself. The story depicts how the bond between mentor and student becomes distorted, evolving into a dark, obsessive relationship.