Mafia's It Boy

Y/N, the newbie in town, travelled half way across the world to be anywhere away from her past life.
Now living with her grandmother and having to start life all over a again is what she really needed but was it the right choice?.

Yeonjun - a normal boy in the day time, no fights, no detention, pretty quiet, only has 4 friends and no one else.
But at night he is the ruthless fighter, cold hearted killer, that has no emotion for any of his jobs.

What will happen when the two of them meet at a very bad time, will it be a happy ending or will it turn out bad for ONE of them.