Divorced from her husband several years ago, Ai is working part-time at a bento shop while raising her son. Her naturally cheerful personality makes the shop a big success, with customers even coming to see Ai! Although they are not wealthy, they lead happy lives. One day, Mukai, a student working part-time at the shop, suddenly confesses his love to Ai, and the excitement of being a woman that she had been suppressing for several years is revived, and they end up having sex in a hotel. From that day on, she forgets that she is a mother and becomes immersed in her love affair with Mukai, who is still hot and bothered by it...