Ichiha came to Box Hell because his wife was too tired from child-rearing and wouldn't have sex with him. There, he ran into 'Kana,' a beautiful mom friend from his son's class. It was awkward, but she kindly took care of him, saying, "It'll be our little secret?" Although he felt guilty, the thrill of having his wife's mom friend take care of him overpowered that feeling, and he found himself going back to Box Hell again.
