We are in 1916 and the Great War is tearing Europe apart.
With Germany running out of soldiers and recruiting in Denmark, Erna fights to keep her 17-year-old son, Kalle, out of the war. When Kalle is forcibly conscripted, Erna makes the perilous decision to cut her hair and swap her identity with that of a deserter to follow Kalle's battalion. The only way to stay incognito is to volunteer for the front lines. They find themselves in the bloody front lines at the Somme. Erna falls in love with Private Anton when Kalle goes missing during a grenade attack, and Erna fears the worst. Not knowing what happened to her, Erna crosses the battlefield to find the trace of her son. Along the way, her true identity is revealed and she must accept being a woman in this world of men.
This change gives her new strengths and opportunities on her journey to find Kalle – and find herself.