The Edge of Hell: The Mitchell Brothers Series Book One

Corporal Mae Stoker is no stranger to misery or surviving harsh conditions, especially after enlisting in the Union Army at the height of the American Civil War to avoid living with her aunt and uncle. But when she's wounded during the Battle of Lovejoy's Station, Captain Wolstan Mitchell discovers there's a female in the ranks and makes a rash decision to save her life, forever intertwining their fates.
After leaving Mae with his doctor uncle in nearby Jonesborough, Georgia, Wolstan is captured and imprisoned in Andersonville Prison for nine months. When he finally returns home to Chattanooga, Tennessee, he is a tormented shadow of the man he was before, unsure if the brokenness inside him can be or is even worth fixing-until learning love has the power to mend even the most shattered souls.