Cut to the Heart (Electronic book text)

Inspired by the true heroism of legendary nurse Clara Barton, founder of the American Red Cross, award-winning author Ava Dianne Day weaves a suspenseful blend of fact and fiction in a gripping historical thriller set against the violent upheavals of the Civil War.
Assigned to Hilton Head Island, headquarters of the Union Army in the South, Clara Barton finds herself in a limbo that is neither battlefield nor hospital. Here, among emancipated former slaves, Barton must look after wounded Colonel John Elwell--and learn all she can about the community's folk medicine. But while she longs to return to the front line, she soon discovers the isolated settlement has perils of its own.
As Clara's suspicions escalate, historical events propel the "Angel of the Battlefield" toward a confrontation as old as time itself. On one side stands Clara Barton, the epitome of goodness and humanity; on the other, a sociopath possessed of a mind as brilliant as it is depraved.

"From the Paperback edition."