Answer the following question: Given the below context:  In 1942, Nazi Germany attempts to bring neutral Turkey into the war on its side by staging an assassination attempt on Franz von Papen, its own ambassador to the country. Much to the annoyance of Colonel Robinson, von Papen survives and the Russians that his agent provocateur was trying to frame have solid alibis, forcing him to turn to another scheme to inflame Turkey's traditional rivalry with Russia.  Meanwhile, American machinery salesman Joe Barton boards the Baghdad-Istanbul Express train at Aleppo and is attracted to another passenger, Ana Remzi. She is worried about being searched by customs agents once they reach the Turkish border; she asks Joe to hold on to an envelope containing some securities, all that remains of her inheritance. Joe obliges, but when he later examines the envelope, he finds maps of Turkey with writing on them. When they stop in Ankara, he goes to her hotel to return her property, only to find she has been fatally wounded. He hides when someone else approaches the room. He watches unobserved as Soviet spy Nikolai Zaleshoff searches the dead woman's luggage. Then, Joe exits through the window. Leaving the scene, he is seen by Tamara Zaleshoff, Nikolai's sister and partner in espionage. The Turkish police take Joe in for questioning, only it turns out that they are German agents. They take him to their leader, Colonel Robinson. Robinson wants the maps. Joe refuses to cooperate, and is taken away to be interrogated by Mailler. Before the Germans get very far, Joe is rescued by Nikolai. When the Zaleshoffs reveal that they are Soviet agents, Joe agrees to fetch them the documents. Unfortunately, he finds his hotel room has been ransacked and the documents stolen. Joe, it turns out, is also a spy (for the United States). When he reports to his boss, McNamara, he is assigned an assistant, Hassan.  Guess a valid title for it!
Answer:
Background to Danger