MKON-138 Serious girlfriend in a serious relationship is cuckolded by a charlatan and turns out to be a born-again penis fiend, Miko Kojima.

Miko and Yoshio, who had been in a healthy relationship, are photographed by Saito kissing after Miko hands him a condom on the way home from a date. Saito blackmails Miko and forces her into having sex with a condom. Miko is completely corrupted and starts begging for unprotected sex, but she still doesn't want to break up with Yoshio. She keeps saying that she still loves Yoshio, but in reality, she's addicted to the pleasure of cheating and having sex with him...