Park Sanghyun. The innocent man he used to be died a long time ago.

Three years to be exact.

Three years since he disappeared and no one was able to bring him back.

Three years of pure sorrow and despair.

Three years since a new man came in.

A cold-hearted young man who doesn't believe in mercy and doesn't give his enemies, who crawl at his feet, any pity. He goes on with his life by killing, drinking and getting laid. We call him Cheondung. Holding the meaning of thunder, he received his new name from his boss meaning that people would tremble at his feet. He is part of one of the biggest gang in South Korea, as many others in the underground world fear them. They are called MBLAQ. What does it stand for? Nobody knows. Along with his four other brothers, they face this harsh cruel world that took everything from them. Whether they lived a happy stable life in the past, each of them, somehow, stumbled in the world of violence and death. Raised by one of the most respected man of all the country for the past four years, those boys grew up to be the young men they are today: fearless and heartless.

Well only one of them was.

Everything changes once Cheondung meets her. The young woman who will bring a sense of color into his life. Once they will meet, her life will turn upside down, bringing total chaos into her peaceful world. Why was she brought into his world? Only God knows. She can't seem to escape this situation, neither does she wants to; in the end, she grows to accept her fate. Maybe destiny has a funny way of showing her what she really needs, which was placed right in front of her on that fateful night she first met the God of pain.

Will she be able to melt his frozen heart and bring him back to life?