Aimi's ex-boyfriend Okuda, an ordinary housewife, is a college classmate with Aimi's husband Yoshikawa. And Yoshikawa's step-brother, Tsuyoshi, is a senior and junior in college with Yoshikawa. Aimi is trying to sort out her affair with her Okuda without her husband's knowledge, but Okuda, who knows her well Aimi, doesn't let her go, and tries to make her realize that she's dissatisfied with her affair with her Tsuyoshi. to her couple's trip. Due to her unspoken promises between Aimi's ex-boyfriend Okuda and her stepmother Tsuyoshi, Aimi gradually opens her eyes to her own sexuality...