The theater contains a movie screen and a wooden stage adorned with red curtains. The curtains apparently closed or opened to a certain length to accomidate the ratio of a film playing on the screen.
The theater's area is dark while the beginning of Mickey's cartoon plays out. About a minute into the film, the villain Peg-Leg Pete throws Mickey Mouse and Horace Horsecollar through the screen and into the theater. After Pete closes the hole, Horace walks into the screening room from the concession stand, having apparently stolen some snacks and a smartphone. Mickey gets the idea to make Horace into a makeshift biplane to attack Pete from outside the screen, but they instead fall through the stage, creating a hole. After a situation where Pete falls into a lake and water fills up the screen, Mickey pokes a hole in the screen, at first creating a small leak, then a massive flood once Pete's size expands the hole and him and Mickey's friends are washed up onto the stage.
After a chase in and out of the screen, Pete pulls down a new unopened screen and bolts it shut by firing nails from his mouth. Mickey and his pals soon realize that they can control the action in the cartoon by flipping the screen on different axis. After Pete is defeated, Minnie Mouse drives his car through the screen and demolishes it, after which everyone goes in and pulls down another screen to seal Pete out. When Pete attempts to get back into the screen through the iris-out, the stage is left a mess with the floor broken, pieces of screen scattered around and Pete's car wrecked in the seats.