Aki had developed feelings for Yasaki Yui, who had recently moved in next door. One day, he bumped into her in the hallway as she was taking out the trash and instantly fell in love upon seeing her braless and pantyless body. In that moment, Aki accidentally left behind her underwear, which he then treasured as a precious object for masturbation. Obsessed, he fantasized about Yui's seductive figure and imagined having sex with her. Later, while Aki was masturbating with her underwear, a heavily intoxicated Yui showed up at his room. Invited in to care for her, Aki gave in to overwhelming temptation and ultimately ended up sleeping with her.