When Choi Heejin's fiance, Sungyeol, dies, she is taken under the care of his gang members, Sunggyu, Sungjong, Woohyun, and Myungsoo. She is trained to replace his position, and the affair is emotionless. She is left crying herself to sleep, no one comforting her, yeah, it's no fun being Heejin. When her first real battle comes after a few months of training, she spots Sungyeol's killer and is driven by emotion, wanting to avenge him. Memories with Sungyeol comes back to her and brings her back to stage 1 of the grief. This time is a little different, Woohyun has grown closer to her. He's there to listen to her cries, treat her to ice cream, the movies, and it's all very new for Heejin. She had thought the guys were cold and didn't like her, but now Woohyun had cleared up that it was only because they were slow to open up.

Slowly, Woohyun begins to replace Sungyeol; he's the one to take her out, make her smile, brew morning coffee for, give back hugs to, Sungyeol is slowly forgotten. But there's so much Heejin doesn't know about Woohyun that she should, and maybe he's not the perfect guy she thinks he is.