After a traumatic deployment in Afghanistan, twenty-three-year-old Army medic Blanca Hernandez is ready to leave the life of a soldier behind so she can help her younger brother Mateo start college. His orientation goes awry when a secret university experiment malfunctions and sends Blanca, Mateo, and several others back in time to Nazi-occupied Poland. Just like that, Blanca is back in a war.

Matters are complicated further by the arrival of Otto Zimmler, a Nazi fighter pilot 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.