The monster is the best friend I ever had- Luhan

Now I know what a ghost is. Unfinished business, that's what.- Yumi

I don't want to hurt you. Though I do have to kill you.- Yura

Plot

Luhan and Yumi were best friend since birth. Yumi was a cute, bubbly and beautiful young girl. One day, when both of them were 6 years old, they were playing hide and seek in Yumi grandparent's house. Luhan was it, he counted. Yumi hid in the guest room. Luhan went to find her. Luhan went into the room, the room they were told strictly about not to enter. 

Luhan had let the dead out. Though the dead was evil, she was known by the grandparents as a demon. She was evil, yet she falls in love. She love too deep, she kill. She turned into a real demon. She wants to get all she wants to herself. One person on her list, she need to get rid of. Yumi. She need to get rid of Yumi, to get what she love, who she love. Luhan.

Luhan unlocked her, yet she does not haunt him. She haunt her. She makes her suffer. She knows it. It was her plan.She makes Yumi suffer the way she did. The loneliness, emptiness, half alive and  the pain of heart being stab but never dies.

But there is one thing she miss, Yumi had became stronger than she was. She's the Yumi, Shin Yumi. She isn't easy. No one can bring her down, not even the dead. Each time she tries to bring Yumi down, she come back up two times stronger. She want to befriend Yura. She will...