What Who Is the Real Heiress? is about
Separated sisters Kim Yun-hee and Kim Ji-won grow up in different worlds. Ji-won becomes the heiress of a wealthy family, while Yun-hee builds her own company overseas. When Ji-won's death is ruled a suicide, Yun-hee suspects murder. She assumes Ji-won's identity to uncover the truth. But as she gathers evidence against Ji-won's corrupt husband, the real Ji-won returns—having miraculously survived.
