Denmark, 1918. WWI is raging through Europe. Germany is so low on soldiers, young Danish men are being drafted to join the war. A group of soldiers headed up by Officer Meyer show up at Erna's house to enlist her 17-year-old son Kalle in the German army. Determined to stay close to Kalle, Erna takes drastic action: she takes on the identity of a soldier who has deserted ranks, so that she can follow Kalle's unit and protect him. To get support, Erna makes a secret pact with Officer Meyer, who takes a liking to her. But soon Erna finds herself trapped in her disguise as a man, in a violent world of men, heading off to battle on the front lines. She also has to come to terms with Kalle's new determination to find his own way amid the horrors of war. As she learns to let go, Erna will finally open up her heart, discover passion and free herself from the dark secret she has been holding in for so many years.