Yuri lives with her son. One day, she asked for one thing she wanted in celebration of passing college. Then she asked for sexual intercourse with Yuri. And Yuri blurts out things that aren't even on her mind. She said, "Only once. Can you promise?" she said. The two then piled on top of each other. It's a one-time thing before and after. One day, Masaaki invited him to a hot spring trip to remember his last mother and child. Lily happily agreed. While she feels a premonition that something is about to begin...
