Ellen Lange escapes from a boarding school for girls in Hamburg and goes to her brother in Kiel, who has to leave to fulfil a secret order in England. Ellen travels to Berlin, where she meets a girl. Lady Jenny helps Ellen to get a job in a music store. Her boss Mr. Hansen instructs her to bring a valuable violin to Copenhagen. There she discovers stolen secret documents from Berlin in the violin and decides to work for the German secret service. She travels back to Berlin to denounce the music store. The secret documents in the violin lead to the sinking of the U-boat where her brother was. Together with an agent she wants to fulfil this difficult espionage order that leads both to London. But there she is recognized and imprisoned…