Most murderers are cruel, ruthless, and have little or no feeling when it comes to the ultimate point of their job: killing someone. 
But in one individual's life, that is not the case. Oh Sehun grew up well. He had loving parents, two fathers, who loved him very much. So, naturally, he was raised to be a very polite young boy. So polite that even his brutal job that he inherited from his fathers didn't stop his kind and polite attitude. 
When his boss assigns him to kill Luhan, his last target before he can live a normal life again, Sehun thinks nothing of it and proceeds to do his job normally. 

How will the situation go once he meets his final victim?