Stamboul Quest

It's unusual in that the story is about espionage and counter espionage (and perhaps counter counter espionage) among the Germans during World War I, at a time before America entered the war.

Myrna Loy plays a German spy, sent by her spy boss (Lionel Atwill) to find out whether the head of the Turkish forces (very well played by C. Henry Gordon) is a double agent, spying for the British. The Dardanelles are involved, and military secrets. Myrna's life and mission are complicated by the fact that George Brent, an American studying medicine in Germany, is accidentally arrested in a dentist's office, during the ambush of Leo G. Carroll, who is also a double agent. Rudolph Amendt (who would play the mad doctor in She Demons nearly 25 years later) has a small role.

There are nuns in this movie, and a convent, at the opening and closing. Myrna, having outed Mata Hari as a double agent, herself falls in love, jeopardizing her work. There is some very clever dialogue in this film, as well as a little bit of well placed humor, and a great scene in which C. Henry Gordon writes secrets in invisible ink on Myrna Loy's naked back.