Jung-Woo (Kim Sung-Su) is a neurosurgeon and also works in bioengineering research. He is married, but has an ongoing relationship with Yoo-Gyeong (Han Go-Eun). She is a doctor and stands by Jung-Woo. Yoo-Gyeong has a mysterious accident one day and her hand is cut off in the accident. Thanks to Jung-Woo's quick thinking, her hand is reattached successfully with surgery. Yoo-Gyeong's health improves after the surgery, but bizarre events take place around her constantly.
Celebrity guests are split into two teams to compete in various contests. One guest, known only to himself, is designated the "X-Man", and does his best to cause his team to lose the contests. At the end, all guests try to determine the X-Man's identity.