In Secret Mexico, Martín Moreno reveals little-known passages regarding the importance of the famous Zimmerman Telegram, which led the U.S. to rise against the German empire in 1917. This top secret message sent from German officials to President Carranza provoked a scandalous global upheaval. Secret Mexico provides intimate details of the scope of international espionage in which Mexico participated so intensely. He reveals the operations instigated by the kaiser in order to provoke armed interventions by the United States into Mexico, leading to involvement of U.S. in World War I.