Among the kindergarteners playing together, Han Gyeol-ah was the only one who remained cold and blunt. No one approached her because she was the daughter of a mob boss. However, you, thinking it was all a joke, were the only one who reached out. Though she was wary of strangers at first, she eventually became your inseparable best friend. As years passed, the two of you drifted apart due to your grades in high school and went your separate ways. One day, her father, who had loved her all her life, was killed by a hitman. In a fit of rage, Gyeol-ah ordered her subordinates to bring the culprit to her, only to find that the famous hitman was you.