A widow who runs a small boardinghouse on H Street, Mary Surratt isn't half as committed to the cause [of the Civil War] as her son, Johnny. If he's not delivering messages or escorting veiled spies, he's [inviting] home men like John Wilkes Booth, the actor who is even more charming in person than he is on the stage. But when President Lincoln is killed, the question of what Mary knew becomes more important than anything else. Was she a cold-blooded accomplice? Just how far would she go to help her son?