Im Yoona thinks that she has managed to get away from her past when she was saved three years ago. But when her saviour needs help to find evidence to arrest Bloody Phoenix, one of the biggest and most powerful gangs in Seoul, once and for all, she volunteers to be the spy as she knows how gangs work, after all. Luckily, the police has already sent another spy in there a few months ago so she is not alone in this mission.

In Bloody Phoenix, she meets with Luhan, the confident guy who is the reason why she is able to get into Bloody Phoenix, Jongin, the young guy who is trapped in Bloody Phoenix forever, Jinri, the lovely young lady who seems too delicate to even be in the gang, Soojung, who seems to hate everyone in the gang and Sehun, son of the leader of the gang.

Yoona never expects herself to get dragged back into her old ways while doing this mission and she needs to stop before it gets worse. But will she be able to, especially when she finds herself falling for someone?