Cha Yo-Han—an arrogant but genius doctor of anesthesiology—and Kang Shi-Young—a smart, warm resident of anesthesiology—work together to help people with mysterious cases of acute or chronic pain.
There is an emergency patient who needs treatment immediately at Chungil Penitentiary. The warden calls 911, but Yo Han secretly appears and treats the patient. Si Young plans a trip to Madagascar, but she is short of money. At that moment, Jeong Nam calls Si Young and offers her a part-time job.