His girlfriend's friend, who he shouldn't touch, is too erotic, so he gives in to temptation and ends up having sex with her! Taichi's girlfriend, who he lives with, is going on a family trip for about a week, and he's going to be alone for the first time in a while. However, before she leaves, her best friend Nanami comes to visit, and while she's drunk and sleeping, he suddenly becomes close to her. After she leaves on her trip, Nanami comes to visit again, and for the week until she comes back, he and Nanami start living together and having sex every day, with him having sex every day...