A house guest becomes the focus of Alice’s schemes. When Mary falls ill, Foster’s attempts to care for her antagonize the new chief. Charlotte tries to contain the smallpox epidemic and Samuel has to make a difficult decision.

President Lincoln’s visit sets in motion a diabolical rebel plot and offers an opportunity to free James Sr. Dr. Foster uncovers a scheme to undermine him at the expense of his patients. Aurelia recovered from her surgery makes a bold decision.

As Pinkerton looks at the Greens more closely, they join forces to hide an ugly secret. McBurney, hoping to distance Foster from Mary, sends him to a nearby army camp on a house call. Alice helps Frank escape and Samuel earns Charlotte’s respect.

After Antietam, the Greens suffer a setback and Pinkerton’s inquiry heats up. Foster and Samuel visit Foster’s family plantation, where they intervene in a difficult labor. The hospital staff unites to oust their hated chief.

New England nurse Mary Phinney navigates her first day in Mansion House, a hotel turned Union hospital in an occupied Southern town. Mansion House owner James Sr. struggles to preserve the family fortune as daughter Emma secretly searches for her beau.

Confederate belle Emma nurses her wounded friend. Dr. Foster wrestles with his marriage and career as Mary tries to improve her patients’ lives with Samuel’s help. Aurelia submits to Silas’ advances in exchange for his help.

Dr. Foster confronts his family’s divided loyalties when his mother and wounded Confederate brother arrive. Alice is shocked to find her fiancé, Tom, deeply changed by war. Samuel and Aurelia try to persuade a slave boy to seize a chance at freedom.

During a Union ball at their house, the Green girls and Frank initiate a daring plan to help Tom escape. Mary releases Dr. Foster, still shaky from his detox, from his “quarantine” so he can guide Samuel through a delicate operation.