During World War II, Germany (and other major combatants) sometimes struck at their enemies using tactics other than brute force. Sun Tzu once said all warfare is based on deception, and I think that sums up this film quite well. Otherwise known as How to Operate Behind Enemy Lines, Undercover is a film made for the Office of Strategic Services, which was an intelligence agency employed by the US during the war. Basically the forerunner to the CIA, the OSS used spies, trickery, and other underhanded strategies in order to sneak into Axis controlled territories so they can gather information on what their enemies are focusing on. During a conflict, info is power, and the more you have of it, the better. In the film, we see legendary director John Ford in his one and only speaking role. In real life, Ford was commissioned as a lieutenant commander (equivalent to a major in the Army and Marines) in the navy reserve and was also made head of the photographic unit attached to the OSS. Here, he plays an OSS officer who is tasked with making sure new spies are able to successfully infiltrate hostile territory without getting discovered. There really isn't a plot, but there are two spies involved working for the OSS (named Charlie and Al), and we see how important it is for them or any saboteur to adhere to a believeable story when it comes to being an agent. For instance, before Al is sent off, he has to tell his superior what his background is just in case a Gestapo officer in Nazi Germany stops him. He says how he used to work at GM in the 20s, then moved to germany and started working there. His entire story seems like it would fool a cop, except for one thing: he mentions at the end how he has something wrong with his back. Al's boss says you should never say anything you can't prove, as this can sometimes jeopardize your entire mission. Remember, cops, the government, bartenders, and even landlords being in league with counter-espionage agencies isn't unique to nazi germany, and if you act suspicious, you can get reported and your cover will be blown. In another example, a german spy lands in Canada, saying he's from the western province of British Columbia. His disguise and way of speaking fools pretty much everyone, and it looks like he's going to get away with spying until he pays for his drinks. Without thinking, he hands the bartender an out of date canadian dollar, which is a fraction of an inch longer than the more recent ones. He is arrested shortly after. Across the Atlantic, Hitler's ruthless bodyguard detail, the SS, are questioning a brit they suspect to be a spy. The latter has a convincing backstory as to what he does for a living, but he makes a fatal slip when his interrogators find hair grease on his head: a british product not seen in germany for years. After seeing how such slight details can fatally punish you, it's no secret why the OSS repeatedly tells its recruits that it's not enough to look like the person you're disguised as, you have to conform yourself to his identity. If you're sneaking into germany as a mechanic, you should never carry anything incriminating on you. You also shouldn't ask random vehicles on roads to pick you up, as there's a good chance a government official is driving. If you plan to stay at a hotel, it needs to be one well within the price range of what a mechanic can afford, and if you plan to enlist the help of someone to find your way around, you better be careful. People who are part of the anti-nazi French Resistance are a safe bet, but anyone asking for cash in exchange for showing you where you are is not to be trusted, since they're only loyal to money. While not mentioned in the film, it's worth noting the OSS ran a campaign of making fake articles for german audiences that claimed soldiers on leave could sleep with any woman in germany. The OSS infuriated nazi high command so much that Hitler ordered any agent taken alive to be executed. This was quite an interesting thing to sit down and watch. Being a spy during ww2 was no easy task, and is in my opinion the most difficult role on the battlefield to master. All the things and prying eyes you have to work around, the dangers you throw yourself in the center of, etc. It's not easy, but they played a crucial part since keeping their eyes on what the enemy was doing allowed america to change its tactics depending on the situation. No single strategy is the best one.