Epoch -- Kat Elle, Hardcover

Embittered twenty-three year old Army veteran Blanca Hernandez houses her emotions at the center of a steel trap, and for good reason. Nothing in her life has been easy, starting with a rough childhood in foster care. Now, though, things are looking up. Her deployment is over, and she has just returned from Afghanistan to Texas, where she plans to send her younger brother Mateo to college. His orientation goes awry, though, when a secret university experiment malfunctions and sends Blanca, Mateo, and several others back in time to Nazi-occupied Poland in 1943. Just like that, Blanca is back in a war. Matters are complicated further by the arrival of a cocky Nazi fighter pilot named Otto Zimmler, who agrees to help them in exchange for his freedom. Now, Blanca and the others must fight to survive the elements, avoid hostile soldiers, and keep the timeline intact - all the while never letting Otto know the truth of their origins.