Mistaken unfaithful wife - Reunited with ex-boyfriend at class reunion -

Miho married her husband who was her classmate at university. One day, she ends up attending a class reunion, where she meets her ex-boyfriend Kozuka again. Miho feels the excitement of her younger days when they meet for the first time in a while, but she doesn't want to ruin her current life and treats him as a friend. However, Kozuka was not like that. Unable to forget about Miho, he took advantage of the time when her husband was not home and visited her house, asking for a relationship. Miho couldn't refuse it, and though she felt guilty, she felt like she was experiencing a cock other than her husband's for the first time in a while...