Yeo Wook is a first-year neurosurgeon at Seoul Korea Hospital. Born with intelligence and into a wealthy family, he is called "his egocentric highness" because of his arrogance. But he has compassionate love in his heart and is determined to conquer the brain by becoming the best surgeon. Hae Jo is a competent and passionate first-year neurosurgeon in the same hospital. Yeo Wook runs into Hae Jo when he visits the emergency room of a rural hospital and gets into an argument with her about how to treat patient. Eun Hyun is a cold, workaholic fourth-year chief neurosurgeon surrounded by an aura of mystery. He becomes more and more interested in Hae Jo, who continues to grow by overcoming various problems. Tae Jin, Yeo Wook's father, is a great neurosurgeon, who is also faithful to his family as a considerate father and husband. He is respected as a 'living saint' for proactively operating on patients without family or friends, but he believes that even his wife can be subjected to an experiment to construct a complete map of the human brain. As the long-buried secret around Tae Jin starts to unveil, the young neurosurgeons are swept away by fate.