Kenichi returns to his rural hometown for the first time in a while to visit his family. His stepmother, Yumika, warmly greets him with a gentle smile, but Kenichi can't help but notice her mature, voluptuous figure, stirring unexpected desire within him. The next day, alone in his room, he indulges in masturbation—only for Yumika to accidentally walk in on him. Instead of anger, she responds with surprising tenderness, enveloping the flustered Kenichi in her warmth and kindness, deeply stirring his emotions.