In the underworld of a dark fictional city, Jang Tae-yeong (Kim Soo-hyun) is a successful problem solver as well as owner of a large casino. Disturbed by an entirely different personality lies within himself, Jang decided to seek the help of Dr. Choi Jin-ki. To help Jang be rid of the other personality, Dr Choi came up with an elaborate plan. Jang followed through the plan, however, it yielded unexpected consequences. The battle of the real and fake Jang Tae-Yeong then ensues...