I still can't forget it. That gut-wrenching incident happened in the spring of the third year after I married Sana. Bored with her life as a housewife, Sana said she wanted to learn how to use a computer in order to get a job. By chance, her best friend Yoshida agreed to teach her, and from that day on, Sana began visiting Yoshida's house. Day by day, Sana's behavior became stranger, and I became worried, so I decided to sneak into Yoshida's house. There, I witnessed a shocking sight...