New Heart follows the lives of chest surgeons, a practically dying breed of surgeons in Korea due to its high-risk factor and low cost for the amount of time spent in surgery. Choi Kang-guk (Jo Jae-hyeon) is a brilliant chest surgeon, but he has self-confined himself in the countryside. But due to his brilliance, he is persuaded to come back to the city to head the team of chest surgeons. Two fledgling doctors enter into his care: Nam Hye-seok (Kim Min-jung), the top of her class, and Lee Eun-sung (Ji Sung), the clueless one who just wants to be a doctor. Through tears and laughter, they learn about love, saving the lives of patients, and what it truly means to have a new heart.