The world of Mercy Street comes as a rude awakening for Mary Phinney. Hailing from liberal, forward-thinking New England, she is a woman with a strict sense of right and wrong, with slavery obviously falling into the latter category. But, arriving as head nurse at Mansion House Hospital, Mary is about to realise she can't judge everyone according to her own standards. She's soon forced to accommodate Southern customs and prejudices, and deal with the messy moral complexity of life in a warzone. With secret schemes and corrupt conspiracies all around her, can Mary maintain her own strength and independence?
Emma is, in many ways, the polar opposite of Mary. Where the latter is a keen-minded Northerner crusading to right wrongs, Emma is the stereotypical Southern belle: coy, casually flirtatious, inhabiting a fairy tale existence. At least to start with. Thrown into the tumult of war when the Union soldiers take over her town, Emma has a serious amount of growing up to do. And when she starts working at the hospital as a volunteer nurse, she gets a whole new view of the world, turning her previously pampered and privileged life upside down.
There's more than meets the eye with Samuel Diggs. He may work as a mere hospital orderly, but Samuel is a dab hand with a doctor's scalpel, having picked up some clever surgical skills thanks to his upbringing as a servant in a doctor's house in Philadelphia. But, as he is a black American, Samuel has no hope of properly applying his knowledge, and has to tolerate the everyday bigotry of life in Alexandria, while secretly striving to make a better life for himself. His ambitions may be thwarted by his growing affections for an escaped slave, however.
DR JEDEDIAH FOSTER
Jed Foster is a man ahead of his time. An army surgeon mired in the blood and guts of war, he is passionate about progress, and uses cutting edge medical techniques which baffle and even annoy his fellow doctors. Not that that will stop him. Jed can be a stubborn man, and that applies to his views on slavery - having grown up in a slave-holding household, he is slow to acknowledge the cruelty of this Southern tradition. That said, his burgeoning friendship with Mary may just make him see the light. He also has his personal demons to vanquish, including a worrying dependence on morphine.
JAMES GREEN JR
The Green family is the Southern dynasty which actually owns the hospital building. And the heir to the fortune is James Green Jr, very much the black sheep of the family. Treated as a runt by his overbearing father, James is bitter, frustrated and self-conscious - particularly as his club foot has prevented him from doing his bit on the frontline for the Confederacy. Prickly and filled with inner rage, James is desperate to make himself into the perfect Southern gentleman - but will his burning ambitions lead him down dark and twisted paths?
The advent of war has changed everything for Aurelia. Once a slave, she's now officially designated a "contraband" - this means a slave who has escaped her owners and sought refuge in the Union. Her early years were horrific, but now she's in Alexandra, she has the opportunity to re-make her life from scratch. But, as a young black woman, she is more vulnerable than most, and the attentions of the lascivious, manipulative hospital steward Silas Bullen may keep her entrenched in a new form of servitude. Could her growing relationship with Sam Diggs prove the way to a better future for this freshly liberated woman?
DR BYRON HALE
While Jed Foster is eager to apply bold new surgical procedures, his colleague and rival Byron Hale has a rather more old school attitude. This veteran army surgeon has no time for clever new techniques, preferring his own tried-and-tested methods for helping injured soldiers. While he may be pompous, smug and self-centred, there's no denying Byron is also a brilliant medic whose services are essential in the desperate world of the hospital. Some may call him an ego-maniac, but Byron would simply call himself a survivor - determined to make the war work for him.
Dashing, handsome and secretive, Frank Stringfellow sets ladies' hearts a-flutter, but romance isn't the only thing on his mind. He happens to be a Confederate spy, deployed on daring missions to scupper Union plans in Alexandria. Fiercely devoted to the Confederate cause, Stringfellow is a dangerous man to cross, all the more so when he gets caught up in a vehemently pro-slavery group known as the Knights of the Golden Circle. He does have a soft spot though, and that's his deep love for Southern belle Emma Green.