Sensing that Ko Seung-tak, a resident at Eunsang University Medical Center, will not get along with him, Cha Young-min, the top cardiothoracic surgeon, plans to get rid of him.

Young-min finds his body in a critical condition and gets confused about if he is alive or dead; Young-min discovers that he can possess Seung-tak only; a mysterious man calls Young-min a coma ghost.

Young-min suspects Seung-tak for the car accident but reconsiders his opinions when Seung-tak makes a sacrifice for him; a VIP patient suffers side effects after the surgery.

With an emergency patient in front of him, Seung-tak struggles. At the same time, Young-min faces the risk of disappearing for good. The two become physically and mentally inseparable, but neither one seems to accept the situation. Meanwhile, Young-min finds out who the wrongdoer behind Chairman Jang’s case is and gets shocked.

Seung-tak has no other option but to ask Young-min for help in saving an emergency patient. While Young-min is impressed with his good faith, he is also shocked and realizes that there is a possibility that Seung-tak might be seeing him. But first things first, the two team up to save the patient.

Young-min finds out from the ghost patient that the accident he was involved in was also planned out by someone. Meanwhile, Seung-jo begs Seung-tak to do whatever it takes to save him. However, the only doctor who can save Seung-jo is Young-min, and the only person who can connect the two is Seung-tak.

Young-min is excited that he can save someone’s life again. At the same time, Seung-tak asks Young-min what it’s like to save a life all on your own. Meanwhile, someone special to Young-min visits the hospital, not as a guest but as a patient.

Young-min reveals the truth about what happened to Seung-tak 12 years ago; Young-min's assailant regains consciousness but cannot remember anything.