Doctor August Durant, Carlo Di Rienzi, and Lili De Neuve watch a film strip on the XB-107, a top secret new aircraft. At reel's end, they are instructed to steal the plans for the XB-107, then sell them to an enemy agent of a foreign power. This agent is already planning on stealing the plans. The Secret Six's mission is to steal them first, then offer to sell bogus blueprints to the foreigner, to take back to his government. Stealing the actual plans will give their ruse the air of authenticity. Durant already has security clearance for moving about the Pentagon. De Neuve uses her disguise skills to conceal herself, and Di Rienzi, behind the identities of General Taine, and his secretary, Marta Swift. Durant leads Di Rienzi and De Neuve to the vault which stores all of the Pentagon's top secret documents. Di Rienze cracks the safe, and removes the blueprints for the XB-107. Suddenly, they are discovered by a guard patrol. To protect his cover identity within the Pentagon, Durant sounds the alarm. Di Rienzi and De Neuve make a run for it, going so far as to beat down Durant, to help protect his cover identity. Di Rienzi takes out the gate sentry with sneezing gas. Under cover of a smoke grenade, Di Rienzi and De Neuve switch into civilian attire, and make good their escape. Durant learns, however, that the blueprints his teammates stole, were decoys. The theft had been anticipated, and the real blueprints removed to another location. Checking on them, though, reveals that the real blueprints have, in fact, been stolen. While the Secret Six were stealing the fake blueprints, the foreign agent used their distraction to steal the real thing.

Durnat determines that Nicolai Sholokov is the most likely suspect. Sholokov entered the country mere days ago, and is already scheduled to depart for the MIddle East. Perusing Sholokov's photographs in the paper, Durant realizes that Sholokov has the blueprints on him. Durant contacts the other half of the Secret Six, briefing them on the situation, and giving them their instructions. Durant and Di Rienzi search Sholokov's vacant hotel room, and find the ashes of the blueprints. Sholokov has photographed the plans, and destroyed the originals. Crimson Dawn is able to book passage on the same flight Sholokov is taking to the Middle East. She takes the seat next to his, and begins flirting with him. King Savage and Mike Tempest rendezvous with the rest of the Secret Six, and travel to the MIddle East in their own private plane. Having won Sholokov's confidence with her feminine charms, Dawn becomes Sholokov's constant companion. Dawn radios the team Sholokov's hotel room number. Savage is dispatched to search the room, while Sholokov and Dawn are away. Finding nothing Savage exits, leaving the room exactly as he found it. Questioning Savage on Sholokov's preference in ties, Durant is certain he knows where Sholokov is keeping the blueprints on his person. Dawn asks to be taken to a local bazaar, where she and Sholokov take in a magic show. The magician, really Di Rienzi, uses a bit of slight-of hand, to swap Sholokov's tie for a duplicate. To further cement his cover as an amazing magician, Di Rienze, with the aid of the Secret Six, performs a spectacular trick, one where De Neuve vanishes from atop a plate of glass.

Back in their hotel room, Durant confirms that the dots on Sholokov's tie are really micro-dot films of the XB-107 blueprints. Dawn is instructed to take Sholokov back to the bazaar the next day. Savage needles Tempest regarding Dawn, nearly bringing the two men to blows. When questioned about his apparent personal stake in this assignment, Durant reveals that agents of Sholokov's country infected Durant with a rare disease. Durant would not have lasted the night, had Mockingbird, the mysterious leader of the Secret Six, not provided Durant with the antidote. The catch, Durant found, was that the antidote only lasted for one day. In return for Durant's servitude, Mockingbird continues to supply him with a pill a day. In the bazaar, Sholokov and Dawn stumble into a brawl between Savage and Tempest. The brawl incites a riot, During the melee, Dawn renders Sholokov unconscious. Di Rienzi replaces the substituted tie, for another substitute. This tie contains fake micro-dot blueprints of the XB-107. Di Rienzi drags Sholokov out of harm's way. When Sholokov recovers, Dawn is right there to comfort him. Sholokov returns to his country, and turns over the blueprints. His government promptly gets to work building the XB-107. During it's construction, the XB-107 explodes, taking their engineering laboratory with it. For his failure, Sholokov is executed. Back at the pentagon, a tie is discovered next to a tape recording. The message played reveals that the tie contains the micro-dot blueprints of the XB-107, returned courtesy of... Mockingbird.