Jung Taekwoon, a guy with a job as a hired killer is also called a "beautiful killer" by his fellow killers because of his good looks followed his emotions and made a big mistake of kidnapping Arielle, a girl who is his deceased ex girlfriend's look alike and also a bait used by the police to catch him and to put a stop to his evil doings but what will happen if the both of them develop feelings for each other? Will he be able to kill her just like what his agency told him to do or will Arielle be able change the beautiful killer's heart and have a happy ending with him?