Twin sisters Yoo Mi-ji and Yoo Mi-rae are are different in everything except their faces. Mi-ji, the younger of the twins, has ended her short heyday as a promising track and field athlete and is currently living a free-spirited life. On the other hand, the older sister of the twins, Mi-Rae, has been walking the path of the elite since her school days and is currently a perfectionist working at a public corporation. The twins, who are physically identical but lead starkly different lives, embark on a bold charade, switching lives for some undisclosed reason.