A man determined for revenge, two girls who are different but came together...

Lee Sung Yeol- just completed training as a killer. First mission is to kill two girls, kim Chung Ae and Park Hye Sook.

Shin Hye Sook-ordinary girl. Very kind and beautiful. Sung Yeol's target.

Park Chung Ae- Rich and nice girl. Knows martial arts. An undercover police that is one of the targets of Sung Yeol.

Mr and Mrs Park-Chung Ae's parents, FBI Agents

Mr and Mrs Shin: Hye Sook's parents. Has a secret that has been kept for years.

Kim Myung Soo- Chung Ae's boyfriend. Works in a entertainment company, but his really identity is...?

Kim Jun Ki-Myung Soo's father. Has a large entertainment company.

Lee Sung Gyu and Kim Eun Na- Sung Yeol's parents. Both professional killers but died when sungyeol was 6.

L-Sung Yeol's mentor who bought him up.always wears mask. Mysterious person.

Hoya-Photographer.Works in the same company as Hye Sook. Has a sweet smile and bright personality.Has a crush on Hye Sook.