Yes, she is a killer. She was abandoned by her father twelve years ago and has already decided on her current path. If Prince Long hadn't taken her in, where would she be? Maybe like her sister, she passed away before she reached adulthood. But what if If she dies, what will she do with her mentally retarded brother and her severely depressed mother? So she cannot die, she must survive, and do whatever it takes to survive. The lives of others are nothing to her, and the world is just a tune in her eyes.
Yes, he is an undercover agent, and his mission is to make her fall in love with him, the mission given to him by the father who abandoned her. As a police officer, what he has to do is to eliminate the bad guys. But are there absolute bad guys in this world? When you think you are the defender of world peace, can you tell the absolute difference between justice and evil?