In April 1917, former newspaperman William Powell is commissioned in the U.S. Army. The day before he ships out for France, he meets socialite Joel Carter at an embassy gathering, and the two spend a bright, urgent day together. Gordon, as the character is known, reveals that he once wrote a book on cryptography under a pen name, a detail that foreshadows the unusual path his career will take. He’s eager to join the fight, even as the Army weighs him for a desk post. Just before his train departure, Gordon is summoned to report to Assistant Secretary of War John Carter, a tense encounter that sets the stage for a covert operation at the heart of the war effort.
Over his objections, Carter assigns Gordon to the code-breaking room to help crack an intercepted German message that Major Brennan has been unable to decipher. Brennan, played by [Lionel Atwill], holds a seasoned but fraying grasp on the cipher, and his frustration is palpable as the clock ticks toward danger. Gordon quickly grasps the stakes: the United States must outpace the German intelligence network that could strand troops and supplies in a dangerous no-man’s-land of sea and shore. As the puzzle unfolds, Gordon learns that Carter is Joel’s uncle, and that Joel has revealed Gordon’s true identity to keep him in Washington, a revelation that complicates loyalties but also binds the two strangers-turned-allies more tightly together.
The film drums up a stark image of the war at sea: the United States is alarmed by the U-boat threat to troop and supply convoys bound for France. To counter the menace, British escorts will meet American transports in a perilous zone, and the rendezvous point will be transmitted only the day before the ships reach the danger. A test run is planned: an ammunition ship is sent ahead to probe the new system’s reliability. But trouble brews at home as a German spy ring in Washington gains access to the code, allowing the test run to glide straight into a trap meant to snare the more valuable transports still to come.
Gordon’s quick deciphering of the intercepted message makes one thing painfully clear: the code has been compromised. He warns his superiors that a convoy has already sailed and that, in three days, the rendezvous location must be conveyed in a code that is no longer secret. The urgency ripples through the rooms and corridors of power as Brennan’s suspicions grow. The spy ring’s reach appears boundless, and the clock is relentlessly counting down.
A central figure in the web of deceit emerges: Olivia Karloff, the spy ring’s asset and mistress to Brennan. Binnie Barnes brings her character to life with a chilling confidence, and Brennan grows more cautious as his own cipher’s theft becomes fodder for scandal. The tension peaks when Olivia is confronted and, in a heated moment, shoots Brennan to prevent his incriminating leverage from spiraling out of control. The immediate fallout forces Olivia to derail the Americans’ investigation, pushing them toward a broader deception that could tilt the war’s balance.
Olivia’s maneuvering leads her to warn Captain Nicholas Nieterstein, an attaché in a foreign embassy who is deeply embedded in the spy ring. Cesar Romero portrays Nieterstein as a calculating, dangerous link in the chain, a man whose fate becomes tied to a notebook and a code book that has somehow fallen into the wrong hands. The circular Michael Reed-style document—containing a message written in a special reagent-revealed ink—becomes the focal point of a deadly ballet of misdirection. When the evidence is finally laid bare, the code book turns up in Nieterstein’s possession, and he is quickly arrested. He reacts with a final, fatal act of defiance, choosing suicide over capture.
Gordon is pressed into service again as the hotel where the ring hides their agents becomes the focal point of a high-stakes showdown. He and Olivia confront the spy ring in a hotel staffed by enemy agents, and Joel, whose jealousy has flared into loyalty and fear, is taken hostage by the conspirators. Under duress, Gordon feigns progress in decoding the convoy’s position while, in truth, he has provided the conspirators with coordinates pointing to the hotel. The Americans decode the deception and rush to act, with Carter’s men storming the building to free Gordon and Joel in a decisive, tense sequence.
The raid reignites the hope that the war can be won through intelligence and nerve, but the victory is tempered by the personal costs and the fraught alliances that brought Gordon and Joel together. As the convoy danger passes and the hotel’s threat is neutralized, Gordon resumes his journey toward France, only to be halted at the last moment by Joel’s enduring influence. She uses her social leverage to keep him in Washington, revealing that, even amid war, personal ties can shape the outcome of global events as surely as any cipher or battle plan.
