A professional killer fell in the shower and lost his memory, swapping lives with others!

Choi Hyung Wook is an experienced assassin who is always able to complete all the tasks given to him perfectly. One day, after making a big deal, Choi Hyung Wook went to the public bathroom to take a shower but unexpectedly fell down because he stepped on the soap and fell into a coma. At this time, the unknown actor Yoon Jae Sung (Lee Jun), who had been secretly watching him from the side, stole Choi Hyung Wook's hand tag and took the money in his locker for himself.
When he wakes up in the hospital, he loses his memory, and with the exchanged hand tag, he thinks he is Yoon Jae Sung and the two exchange identities by mistake. To survive, Choi Hyung Wook started working an odd job and was appreciated by the director because he showed his excellent physical and fighting skills on the set. On the other hand, Yoon Jae Sung discovers Choi Hyung Wook's identity as an assassin and develops feelings for his next target, Song Eun Joo (Im Ji Yeon).