The doctors of Chastain are surrounded by new rules and doctors, as Red Rock Mountain Medical takes over the hospital. Conrad finds himself in a dangerous situation when the construction for a new neurosurgery center causes a gas explosion at Chastain. Meanwhile, new hotshot neurosurgeon Barrett Cain, is put to the test with a complicated surgery and Mina acts as a support for Nic, who is struggling with a devastating loss.
Cain tries to recruit Bell and Kit to join him on a dangerous surgery, with the intent of garnering publicity for the hospital. Meanwhile, the Raptor finds himself with an emotional attachment to a patient whose life is put in his hands and Mina's friend, Adaku (guest star Erinn Westbrook), arrives at the hospital with shocking news. Also, Devon rotates out of the ER and Nic plans a surprise for Conrad
When a police officer shows up to the ER with an injured criminal that he caught in the act, it's up to the Chastain staff to keep him alive in order to save an innocent life. Nic gets roped into a surgical rotation with Cain that leaves her questioning the way he operates, and Conrad makes a shocking discovery about the hospital. Meanwhile, Bell pursues a new fiscal venture that may bring him into a whole new market.
When Devon's patient, who was pronounced dead, suddenly revives, Conrad is left doubting Devon's judgement and wondering what happened. A well-known white supremacist falls under the care of Cain and Nic, causing the two to butt heads on how to move forward. Meanwhile, on their way to a medical convention, The Raptor and Mina get stuck in a strange town, where they uncover new information about Red Rock Medical.
After a plane crashes in Atlanta, Devon is overcome by guilt at the thought that he could have prevented the tragedy. Bell, who was a passenger on the plane, makes it his personal mission to save the life of the man seated next to him. Meanwhile, Adaku returns to ask Mina a big favor, the Raptor struggles with telling his birth parents about meeting his biological father and Conrad and Nic consider risking it all to investigate a drug that might be linked to Jessie’s death.
On National Nurses' Day, Chastain's nurses are severely understaffed and overworked, leaving them all feeling exhausted and underappreciated. Cain performs a dangerous surgery on a new patient he won in a game of poker. Meanwhile, Conrad discovers that his father has been administered the same drug that he fears played a role in Jessie's death, The Raptor comes face-to-face with his birth mother for the first time and Irving attempts to take the next step in his relationship with Jessica.
When one of Chastain's own is brought into the emergency room with life-threatening injuries, the staff rallies around each other to try to save her life, while disagreements over how to best handle her care put Cain at odds with the rest of the doctors. Also, Bell is met with an unexpected response when he voices concerns regarding the nursing shortage that Nic brought to his attention. Meanwhile, Conrad turns heads when he shares data about Hemopleatin, and Kyle begins volunteering at the hospital.
Upon dubbing Thanksgiving “the most dangerous day of the year,” Devon and Irving are inundated with patients in the ER. When an A-list celebrity enters the hospital after swallowing a wish bone, Logan Kim assigns a new surgeon to the case in the hopes of garnering extra publicity.
Conrad comes under fire when a former patient files a malpractice lawsuit against him, putting Bell in a difficult position with Red Rock. When Devon discovers that his VIP patient has a life-threatening brain condition, the doctors ban together to perform a risky surgery. Meanwhile, Mina discovers that Adaku has a dangerous heart condition that puts her and the baby at risk, and Kyle forms a personal relationship with a patient.
On Devon's last day as an intern, he and Conrad are faced with a moral dilemma over a suicidal patient who is in need of a liver transplant. When Bell discovers that Cain is keeping braindead patients alive in order to boost his survival rates and add to Red Rock's profits, he decides to take matters into his own hands. Meanwhile, Adaku goes into early labor, causing a strain on her heart and Mina is left in doubt over how to best handle her care.
After being terminated from Chastain, Conrad has difficulty figuring out his next step and distracts himself by accompanying a patient on a zero-gravity adventure. In his first move as the new Chief of Surgery, Cain puts the doctors on a commission-based pay system, which causes Devon’s new intern to agree to a procedure before weighing the risks. Meanwhile, Mina struggles with taking care of Adaku’s baby and Bell’s supplement company get its big break.
While working at their non-profit clinic three hours outside of Atlanta, Nic and Mina treat a patient with a failing heart VAD, forcing them to find a new battery in time to save her life. Conrad gets a call from a previous patent in crisis after being sued by Red Rock for medical expenses he can't afford. Meanwhile, Devon's VIP patient, Nadine, returns to the ER and Cain tries to get close to Bell's business partner from the supplement company.
Upon meeting with a high-profile soccer player suffering from mysterious symptoms, Conrad ends up back at Chastain and faces an angry Logan Kim. When Bell and the Raptor come up empty-handed in regard to a diagnosis, the doctors take note on how talented Conrad truly is. Nic springs into action when she notices Kyle falling into a deep depression and fears he could be suicidal. Meanwhile, Devon butts heads with Irving over patient space and Mina realizes she has become attached to baby Michelle.
Cain feels disrespected by Logan Kim when he is left out of a major decision regarding Conrad. Meanwhile, the doctors work together to try to save the lives of two big Red Rock donors who were involved in a jet skiing accident. Then, Irving and Devon realize that three of their patients, all with different symptoms, could actually be triggered by the same thing. Also, Bell's supplement company proves to be more lucrative than anyone anticipated, but an unexpected snag could put it in jeopardy.
