Who the Devil Can See in the Dark (2015)

Mari Soppela always knew that her paternal grandfather was a German soldier. In 1944 her grandmother Helvi left Finland secretly with the German army. Later she returned, with a small child in tow. But Helvi never told her son who his father was and Mari's father grew up as a little German in a big Finnish family. Then, in 2010, Mari found her grandmother's interrogation files, which detailed her WW2 love affair. It turned out that the man was already married when he had met Helvi. With this new information, Mari Soppela sets off to unveil her father's father and finds adventure along the way.