It is 1943. A 17-year-old girl, who is a Home Army courier, and an SS officer are travelling by train in the same compartment. The girl is on a secret mission. She is carrying a suitcase with some important documents for Jan Karski. The SS officer is enchanted by her and tries to flirt with the girl. Aware of the danger, the girl keeps an ampoule of cyanide between her teeth the whole way through. She knows what will happen if she gets caught with the documents stolen by four prisoners during a dangerous escape from Auschwitz concentration camp.