In 1940, a foreign reporter, “Comrade X”, is bypassing censors and sending out critical stories about the Soviet Union. Commissar Vasiliev, chief of the secret police, announces that he has taken over the censorship of the press. His predecessor, Comrade Molkov, who was “not watching his step” has been the victim of a “traffic accident.” All reporters will be restricted, unable to leave Moscow without permits. McKinley "Mac" Thompson, secretly "Comrade X", pretends to be an irresponsible alcoholic who skips the news conference.

German reporter Van Hofer has taken over Mac’s room, which Mac has paid for in advance and “fixed up.” “Is this a nice way for a Nazi to act?” Mac asks Van Hofer. Reporter Jane Wilson informs Mac that the funeral will be held that day of Comrade Molkov, shot by his old pal, Commissar Vasiliev, who will now cry over Molkov's grave. Mac pretends to care only about the reception, and Jane expresses disappointment that he was once “the best reporter in the business.” Van Hofer arrives with the Russian hotel manager, complaining that the American has invaded his space. The conversation is interrupted by a phone call, which Mac pretends is the American news bureau notifying that Germany has declared war on Russia (ironically months before Germany’s invasion of Russia actually happened). The indignant Russian manager kicks the German Van Hofer out of the room.

At Molkov’s funeral, Mac spots a pallbearer signal by knocking on the coffin. Using a camera disguised as a portable radio, Mac takes a photo as the assassin rises out of the coffin to shoot at Commissar Vasiliev. Mac hides the film.

Mac’s identity is discovered by his valet, Vanya, who blackmails him into promising to get his daughter, Golubka, out of the country. Golubka, a streetcar conductor, is called “Theodore” because only males are allowed to drive streetcars. Theodore is an idealistic communist, which Mac and Jane proclaim “the worst thing you can be” in the Soviet Union.” Communists are full of ideals dangerous to authorities, so the Communists are executed so that Communism can succeed.

Riding Theodore’s streetcar, Mac pretends to admire the Soviet Union and expresses a wish to help her spread communist ideals in the US. Although initially suspicious of Mac’s motives, with her mentor Bastakoff’s blessing (eager to get rid of a pesky fanatical idealist), Theodore agrees to a sham marriage so she can spread the virtues of Communism to the rest of the world. Unable to marry as “Theodore,” she now takes the name of “Lizvanetchka” (Lizzie), a revolutionary martyr. On their wedding night, Lizzie shows Mac a photo of her idol, Bastakoff, whom Mac recognizes as Vasiliev’s attempted assassin. Jane arrives to ask Mac to file a story for her in the US and exposes Mac as anti-Soviet. After she leaves, the secret police arrive to take Mac and Lizzie for questioning by Commissar Vasiliev.

Awaiting Vasiliev, Mac pretends to not recognize his own radio-camera, which was found in Vanya’s room. To protect Mac and Lizzie, Vanya claims he is Comrade X, showing how cutouts in “his" handkerchief can be used to decipher messages. Mac, Lizzie, and Vanya are arrested. A group of Bastakoff’s followers are imprisoned with them and Lizzie proclaims they would all rather die than betray Bastakoff. Mac relays a proposition to Vasiliev via a guard. He will tell Vasiliev the identity of the man who tried to assassinate him and provide a photograph of the attempt.

When Mac is escorted to “Vasiliev”, he finds Bastakoff is now chief of police. Vasiliev has died of “pneumonia.” The photograph is embarrassing to Bastakoff―as are the 100 Bastakoff followers executed at Bastakoff’s orders to prove his loyalty to the new government. Mac gives Bastakoff the incriminating photo but withholds the negative. Bastakoff exchanges the lives of Lizzie, Vanya, and Mac for the negative, which Mac is to retrieve.

Knowing that Bastakoff will not keep his word―Lizzie now disillusioned―they evade the secret police trailing them, and the three hide on a train hauling tanks. Appropriating a tank, which Lizzie has been trained to drive, they cross the border into Romania, where they surrender and successfully reach the US.

• Clark Gable as McKinley B. "Mac" Thompson
• Hedy Lamarr as Golubka / Theodore Yahupitz / Lizvanetchka "Lizzie"
• Oskar Homolka as Commissar Vasiliev
• Felix Bressart as Igor Yahupitz / Vanya
• Eve Arden as Jane Wilson
• Sig Rumann as Emil Von Hofer
• Natasha Lytess as Olga Milanava
• Vladimir Sokoloff as Michael Bastakoff
• Edgar Barrier as Rubick, Commissar's Aide
• Georges Renavent as Laszlo, world press attendee (credited as George Renevant)
• Mikhail Rasumny as arresting Russian Officer

• Production on Comrade X began filming in late August 1940.
• The film was nominated for an Academy Award for Best Story.

Gable prophetically jokes that "Germany just invaded Russia" and "Panzer tanks are rolling into Ukraine" to get the Russian hotel manager to kick the German reporter out of his room. Less than a year after release, Germany did indeed invade Russia and the Ukrainian SSR.^[3]

Pre-war American films such as Comrade X and Ninotchka also depict the Soviet Union as backwards, dreary, depressing and totalitarian. After the United States entered the war on Russia's side, however, Hollywood's depictions of Russians immediately changed to brave, honorable, freedom-loving liberators. The UK specifically pulled Comrade X from the cinemas.^[4]

At one point in the movie, after McKinley feeds vodka to his secretary Olga and embraces her, Golubka enters his room and the women engage in a "hair pulling battle" for his affections that Variety described as “a honey."^[5][6]

According to MGM records the film earned $1,520,000 in the US and Canada and $559,000 elsewhere resulting in a profit of $484,000.^[1]

• Comrade X at the American Film Institute Catalog
• Comrade X at IMDb  
• Comrade X at AllMovie
• Comrade X at the TCM Movie Database