Marium Carvell

Dr. Sam Griffith (Sophia Bush) fights to keep her new leadership role as chief of surgery when her father and former boss, Dr. Rob "Griff" Griffith (Jason Isaacs), takes his case for reinstatement directly to the hospital board. Also, resident Dr. Caleb Tucker (Michael Stahl-David), Sam's ex, forms an unexpected connection to a patient battling a mystery condition.

Griff completes his proctorship and prepares to make his official return to surgery; hospital board chairwoman Tina Kingsley makes a stunning announcement; the surgical team prepares for a high-stakes lung transplant.

When a gunshot victim is rushed to the ER, the incident triggers flashbacks to the aftermath of Griff's own shooting, and reveals new details of how the people in his life were affected during the six months he was in a coma.

Secrets revealed at a major fundraising gala for the hospital threaten to end a tenuous truce between Dr. Sam Griffith and her father, Griff. Also, cardiothoracic resident Dr. Lex Trulie makes a decision that could alter her career trajectory.

When Amy Taylor (Bethany Joy Lenz) is admitted to the hospital accompanied by her sister, Gretchen (Hilarie Burton), with signs of premature heart disease, Dr. Sam Griffith discovers a deeper medical mystery. Also, Griff anxiously awaits the results of his MRI, hoping to get to the root of his troubling symptoms.