Lim Y/N is a brilliant student and a hardworking older sister who has raised her little sister Ailee alone since their parents' deaths. When Ailee is brutally killed by Cha Eun-woo, the leader of the local mafia, Y/N's world turns upside down. Driven by a thirst for revenge, she teams up with Eun-woo's rival, Bang Chan, the eldest member of the opposing mafia. As she dives into the dangerous world of crime and alliances, Y/N finds herself unexpectedly developing a deep, sincere relationship with Bang Chan. Caught in a web of revenge, justice, and the complexities of the criminal underworld, Y/N must navigate a path filled with danger, betrayal, and ultimately, love. Will she be able to avenge her sister and find happiness in the most unlikely of places, or will the turbulent path of revenge cost her everything she holds dear ?