Mo Mo has two pupils of different colors, one is purple and the other is blue. Mo Mo was very lonely, even her only friend betrayed her without knowing why. Mo Mo has had to survive a cruel life since he was a child. Killer is such a profession. Although he is a killer, Mo Mo still has a kind side in his heart. When she was betrayed by a friend, Mo Mo felt that there was no place for her in that world. Then a man in black appeared...