The top killer of the Nelson family, Jacques, killed his family of three. He accidentally discovered that the young Davion who had helped him before, secretly showed mercy to his men. Davion , who doesn’t know the truth, takes refuge in Jacques, hoping that Jacques will fulfill his promise to teach himself and avenge his adoptive parents! Jackie Kun became Davion’s teacher, and the cold-blooded killer met a pure and beautiful boy like a white rabbit, but gradually moved his heart for him? When will the hidden secret be revealed, and how will the two face it?