Changjo is dating a female idol from a known girl group. Ricky is devastated when he finds out that his long-time crush is dating someone other than him.   Other members try to help him move on but he doesn't do it and then Changjo tells everyone that he's engaged. Depressed Ricky finds himself a distraction in drinking.

Simply said, Ricky is a vampire and Changjo is basically his donator with benefits.