Mei Iikura, a welfare worker, visits the home of elderly man Mr. Satomura, who lives alone. One day, she finds him collapsed and unable to move on the porch, forcing her to take care of his daily needs. As the days pass, Mei grows closer to him and begins to feel his gentle care. One day, while cleaning the stairs, Mr. Satomura suddenly embraces her. Confused yet overwhelmed by his warmth, she finds her face buried between his legs as his lewd tongue passionately caresses her. Shaken to her core by the sensation, Mei loses consciousness. Seeing her helpless state, Mr. Satomura grows bolder, demanding cunnilingus from her even in front of her husband. Each step deepens the emotional turmoil within Mei, marking the beginning of a new, forbidden relationship.