Five years ago, No Seo-yun was framed and cast out after a night at the Lumina Hotel left her pregnant. Alone, she raised her twins through hardship. A chance encounter leads to a flash marriage with Lee Hyun-woo, unaware of his true identity. As she endures humiliation, he becomes her only light—never knowing he is the man from that fateful night.

Separated sisters Kim Yun-hui and Kim Ji-won grow up in different worlds. Ji-won becomes the heiress of a wealthy family, while Yun Hui builds her own company overseas. When Ji-Won's death is ruled a suicide, Yun-hui 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.