Jeon Jungkook, a bodyguard, approached a family with the goal of gathering information himself. He is actually a mafia man... but his face is unknown to people as he usually wears a mask or attacks in the dark. People usually call him the 'death crow' as he takes people's lives in the dark.

But he disguised himself as a bodyguard in order to gather information about a certain family, and became the bodyguard of the son of the richest man in South Korea, as he noticed the difference in the way the girl's family treated her. They paid attention to the family members, and she only received a little, unlike her brothers and sisters. Although she was very considerate and kind, she came across as naive because she was so kind to everyone.

One day, while he was giving her father the application files, he heard her father shouting at her and saying that he would disown her if she did not agree to marry his partner’s son. This was a big deal. Since no one loved her, she was nominated for marriage instead of her sisters...