Every day, the doctors at Taesan Hospital’s Cardiothoracic Surgery Department are faced with life-or-death situations. Park Tae Soo (Go Soo), a fellow in the department, has a personal stake in the matter, as his mother has been on a heart transplant waiting list for four years. He’s highly principled, but sometimes clashes with Choi Seok Han (Uhm Ki Joon), the chief of the department, if he doesn’t agree with particular decisions. However, Seok Han’s hands are often tied by bureaucracy – like when he’s ordered to prioritize saving Yoon Soo Yeon (Seo Ji Hye), the daughter of the hospital’s director, over Tae Soo’s mother, despite having his own personal conflict with Soo Yeon. Can these doctors achieve their personal goals while also saving lives?