At the Midtown Theater in Manhattan, the short subject cartoon is interrupted when the film strip breaks, causing the audience to erupt in boos and hisses. In the projection booth, projectionist Chuck McCann quickly rethreads the film while listening to a radio news report about an elderly man attacked on the Lower East Side. Chuck then imagines himself witnessing the attack. Hurrying into a phone booth, he clumsily begins to pull off his clothes, revealing his Capt. Flash hero suit underneath. Chuck’s thoughts return to the present when Harry, one of the theater ushers, enters the booth complaining about the theater’s curmudgeonly manager, Renaldi. As Chuck tells Harry about sighting The Girl, a beautiful woman walking in the plaza that morning, Renaldi bursts in and chastises Harry for entering the projection booth, which he has designated “off limits” to his ushers. After warning Chuck to stop smoking in the booth, Renaldi leaves and Chuck threads up the coming attractions. As the film runs, Chuck envisions a trailer for The Terrible World of Tomorrow , dealing with “the horror of total holocaust” in which man is destroyed by his own technology. Once the day's screenings are over, Chuck scrutinizes the photos of Clark Gable, Humphrey Bogart and other stars he has pasted along the walls and performs impersonations of them. He then climbs down the stairs from the projection booth, stopping to look at the blank screen. Chuck’s thoughts then return to Capt. Flash as Flash confronts the assailants and saves their victim, an elderly scientist who explains that the thug’s leader, the Bat, is after the x-ray machine the scientist has developed. As the scientist relates his story, Capt. Flash spots a clue the assailant has left behind, a matchbook from Rick’s Café Americain. The scientist then invites Capt. Flash to his castle, and after passing through a landscape peopled by the Wolf Man, Dracula and Frankenstein, they reach the castle. The next morning, Capt. Flash sees the scientist’s beautiful daughter and is smitten. As the couple strolls off into the garden, the Bat’s assailants attack the scientist again and Capt. Flash rushes back to aid him. His thoughts returning to the present, Chuck walks into the lobby where Renaldi is dressing down the ushers for their slovenly appearance. Chuck then proceeds to the candy counter where the elderly clerk complains about Renaldi’s brusque treatment. When Renaldi sees the clerk slip Chuck a free box of candy, the manager insists that he pay for the candy, then instructs the clerk to put more salt in the popcorn so the audience will buy more soda. Leaving the theater, Chuck continues down the street where he sees an ad for the film Barbarella , which triggers his thoughts to another coming attraction, The Wonderful World of Tomorrow , in which the golden age of science heralds peace on earth and good will toward men. As Chuck continues walking along the street, he begins to daydream about Capt. Flash overpowering several of the thugs who have attacked the scientist. The rest of the group has kidnapped the scientist's daughter, however, and so Capt. Flash, disguised in a business suit, heads off to Rick’s Café Americain, hoping to find a clue to her whereabouts. There he finds a discarded business card with a map sketched on the back. Back in his Capt. Flash uniform, he follows the clue to a cave-like hideout inhabited by idol worshippers and a prehistoric monster. Chuck’s thoughts return the present as he passes a theater marquis advertising the premiere of the film Star! Noticing the crowds out in front, Chuck imagines himself being interviewed by an adoring press as his film, The Projectionist , opens. Chuck’s fantasy ends as he approaches the pool room where he is to meet Harry. After finishing the pool game, Chuck returns home and switches on his television. The next morning, Chuck ventures onto the street as his thoughts turn back to Capt. Flash in the cave. Knocked unconscious by one of the Bat’s thugs, Capt. Flash is taken to the Bat’s sanctuary where he is chained to the wall. Boasting he will one day rule the world, the Bat orders that Capt. Flash and the scientist's daughter will perish in the snake pit. As the guards walk them to the brink of the pit, the scientist's daughter karate chops several of the thugs while Capt. Flash throttles the others. The Bat then unleashes an attack by the Ku Klux Klan, Hitler, invading Martians and other evil-doers. In response, Gunga Din then summons the forces of good, represented by Humphrey Bogart, John Wayne, Flash Gordon and Sgt. York, among others. The clash ends as Good defeats Evil and the U.S. flag is raised on Iwo Jima. The Bat has survived, however, and Capt. Flash chases him into the hills where a well-placed punch sends the Bat hurtling off the side of a cliff. Back at the castle, the scientist's daughter and Capt. Flash dance in victory, whirling onto the movie theater stage, where they waltz in front of the screen peopled by Fred Astaire, Ginger Rogers and the Busby Berkeley dancing girls.