V's on the verge of despair ; running away from the town he lived in as a kid has not stopped the onslaught of nightmares whenever he sleeps. No matter where he goes, he is reminded of the sin he has committed. It is why he has decided to live in solitude, never bearing a smile on his face. 

No one is able to help him, not even his friends... until Jieun barges into his life. 

Lee Jieun is everything V isn't ; she's bright, sweet, pure and naive. V shouldn't be interested, but he is. He realises he is not as broken as he thought. She can fix him. She takes her fingers and caresses the cracks in him, mending them.

But he can't. He's not supposed to love, he's not supposed to feel. It was written against the heaven for a mistake like him to love an angel.

He isn't deserving of her.