The story of Unbalance x2 starts up with the main female character, Hae-Young Nah as a young child, Hae-Young and her father was together alone at a park while the sun is setting. She always loves her father and was everything to her, Hae-Young's father always tells her about the true meaning of happiness and that when she finds the right person that she completely trust. But then one day, everything changed on that day. Hae-Young's father disappeared on that day, leaving her alone and completely changing her life. After her father disappearance, Hae-Young never trusted a man ever since her father left her.