Park Si-hoo

 Shin Hye-sun

 Lee Tae-hwan

 Seo Eun-soo

Revolves around a woman who has a chance to rise in status and a man who finds happiness in her. A mother's misguided love has caused her daughters to get swapped in status, and so the heroine Seo Ji-an enters the chaebol household to have a better life without knowing she is actually not their long-lost daughter, but her "former twin" sister instead. What will happen to her once the secret get revealed, and what will happen to her relationship with the son of chaebol family Choi Do-kyung, whom she has gotten closer to as siblings?