Berlin, 1942. When the shy, heavily-pregnant Hilde Coppi is suddenly detained by the Gestapo, she pleads ignorance to their accusations that she has aided her lover, Hans, in transcribing coded radio transmissions to and from Moscow. However, it appears there’s more evidence against Hilde than she anticipated, given Hans and many of the other activists involved in their group – who will become known as Die Rote Kapelle – have also been arrested. Compelled to give birth in custody, Hilde is informed that her child may be taken from her, but her kindness and quiet resolve wins over a prison nurse, enabling mother and son to remain together. As Hilde awaits her sentencing, she reminisces about her involvement with Hans and their joyful romance, the most beautiful summer of her life…