Lilac Girls, the 1.5-million-copy bestselling novel by Martha Hall Kelly, introduced readers to Caroline Ferriday, an American philanthropist who helped young girls released from Ravensbruck concentration camp. Now, in Sunflower Sisters, Kelly tells the story of her ancestor Georgeanna Woolsey, a Union nurse who joins the war effort during the Civil War, and how her calling leads her to cross paths with Jemma, a young enslaved girl who is sold off and conscripted into the army, and Anne-May Wilson, a southern plantation mistress whose husband enlists.