On his last day of surgical residency, Dr. Jung Haejin was hit by a truck, and his life came to a tragic end. Miraculously, he wakes up in the body of Choi Giseok, a soon-to-be surgical intern and Haejin's heart transplant recipient. As he makes sense of his resurrection, he notices holographic screens that only he can see, showing the exact statuses of his patients and medical colleagues. Now, Dr. Choi vows to use this inexplicable power to become the world's best cardiothoracic surgeon.