Follows the lives of two volunteer nurses on opposing sides of the Civil War - New England abolitionist Mary Phinney and Confederate supporter Emma Green.

Based on real events, Mercy Street takes viewers beyond the battlefield and into the lives of a distinctive cast of characters - doctors, nurses, contraband laborers and Southern loyalists - realizing the chaotic world of Union-occupied Alexandria, Virginia, and the Mansion House Hospital in the early years of the Civil War. Written by PBS