My name is Mizuno Masashi. I have been married to my wife Yuka for over ten years... I have lived a life that has nothing to do with immorality. However, it seems that my wife was different. I believed that she was as faithful as I was. And yet, she was having an affair with a young trainer, and I witnessed her climaxing in a way I had never seen before... I would like to show you the whole story, from beginning to end, with the evidence of her infidelity engraved in her diary, and the truth of her betrayal as told by my wife...