During the worst days of World War II, the British government asks the mathematician Alan Turing to unravel the mysteries of the German Enigma encryption machine, an impossible task to accomplish without the invaluable information that Hans-Thilo Schmidt, a disenchanted but greedy German citizen, had been handing over to the French secret services since 1931.

The "For Official Use Only" 2006 training video produced by the Defense Intelligence Agency (DIA) about the case of Ana Belén Montes, a Cuban spy who rose to become DIA's top analyst for Cuban affairs. She was trained by Cuban intelligence in polygraph countermeasures and passed a DIA polygraph screening "test" while spying for Cuba. Includes interviews with Montes' colleagues at DIA. The video mentions (at 16:31) that she used polygraph countermeasures to pass a 1994 DIA polygraph screening "test," which facilitated her espionage: The polygraph test in 1994 made her even more dangerous. By deflecting suspicion away from her, she was freer to pursue her espionage. And to pass the polygraph, she had used a countermeasure taught to her by the Cubans.