After a drinking party with classmates, Sogo, who got dumped and was feeling down, insisted on having a second round at someone's place. However, Sogo got called away by his girlfriend and left right away, leaving Rio and Riko alone. They decide to watch a DVD Sogo left behind, but it turns out to be an "crossing the line with friends" type of porn...!? The two, who actually had a somewhat ambiguous relationship, end up getting turned on by it...!
