One night, Kwon Yisoo somehow mistakenly become the sex partner of a superior he hated, Han Gangjin. Kwon Yisoo tries to break all ties with Han Gangj ...in but during a meeting for his mother's remarriage, he meets him as stepbrothers. He tries to get himself together but because he'll be living with Han Gangjin, Kwon Yisoo can't help but get pulled in by him.