In 1938 Culver, Kansas, a little person named Rollo Sweet lives at a mission, where he awaits a letter from Hollywood regarding an acting role. The residents gather around the radio to listen to an address from President Franklin D. Roosevelt, but the reception is poor. Rollo climbs onto the roof and adjusts the antennae, but falls off. Unharmed, he runs inside to listen to the speech. Meanwhile, in Nazi Germany, Hitler is angered by the President’s address and sends Otto Kriegling, a dwarf Nazi spy, to California to pass secret invasion plans to a Japanese operative dressed in a white suit. At the Culver City Studios in California, studio chief Louis appoints Annie Clark as “special talent coordinator” for the 150 little people arriving by train to appear as “munchkins” in the film, The Wizard of Oz. He also assigns his nephew, Homer, to assist Annie. Homer books rooms for the munchkins at the quiet Culver Hotel across the street from the studio. However, the receptionist hides the reservation so the hotel owner, Lester Hudson, will leave his nephew, Henry Hudson, in charge of the empty hotel and take her to a convention. Meanwhile, Secret Service Agent Bruce Thorpe is assigned to escort a foreign Duke and Duchess and their dog, Streudel, to California. The Duke insists an assassin is targeting him, but no one believes him. On the train to California, the Duke accidentally shoots Streudel while the Duchess is at the bar. As the porter helps the Duke and Bruce find a replacement dog, the Duke reveals that the dead dog is “Streudel the thirteenth,” and his near-sighted wife has never noticed the changing pets. When they reach Union Station in Los Angeles, an assassin makes an unsuccessful attempt on the Duke’s life. Rollo, who was tired of waiting in Kansas, stows away on the same train. As he disembarks, a security guard chases him into the station where Annie and Homer are meeting the Wizard of Oz munchkins, and Rollo quickly blends in with the cast. At the Culver Hotel, Henry Hudson posts a sign renaming it “The Hotel Rainbow.” A bus transporting the Japanese Amateur Photography Society, or “JAPS,” breaks down in front of the hotel, and the Japanese men dressed in white suits check rent rooms. Bruce, the Duke and Duchess, and Streudel reach the hotel, not realizing an assassin is following them. Annie, Homer, and the munchkins arrive at the hotel to discover their reservation is missing and there are not enough rooms. Bruce has booked the entire fourth floor for the Duke and Duchess, and refuses to offer any rooms to Annie, citing security reasons. However, Akido, leader of the Japanese tourists, offers to share some of their rooms, and Annie lends him a copy of The Wizard of Oz screenplay. Munchkins and tourists overflow the lobby as Otto Kriegling arrives, searching for his contact among the similarly-dressed Japanese men, while Nakamuri, a Japanese spy, searches for Otto. At dinner, Otto mistakenly assumes Akido is the Japanese spy and slips the secret plans inside the screenplay. Moments later, Otto meets Nakamuri and realizes he gave the plans to the wrong person. The assassin tries to poison the Duke’s drink, but accidentally poisons Akido. When Annie stops at his table to retrieve the script. Akido drinks the wine and dies. Otto and Nakamuri believe Annie killed him to get the secret plans, but Henry Hudson thinks Akido died of a heart attack and hides the body in the freezer until his uncle returns. During the evening, the munchkins undergo costume fittings and makeup for the next day’s filming. Upon returning from the studio, their shenanigans and parties cause mayhem throughout the hotel. Bruce and Annie’s paths cross as Otto and Nakamuri attempt to retrieve the secret papers, and the assassin repeatedly tries to kill the Duke. Rollo overhears Otto and Nakamuri plot against Annie, and he rushes to her aid. It is a wild night of murder, parties, fights, chases, kidnapping and the blossoming romance between Bruce and Annie. In the morning, Otto and Nakamuri trap Bruce, Annie, the Duke and Duchess, and Streudel in the hotel barbershop. Bruce hides the papers inside a locket on Streudel’s collar and lets him out the door before revealing the dog has the secret plans. Otto leaves Nakamuri to guard the hostages and runs after the dog. As Otto chases Streudel onto the studio lot, Rollo rallies the munchkins and they pursue the spy through various film sets. Meanwhile, the assassin sneaks into the barbershop to kill the Duke, but he and Nakamuri kill each other. Bruce and Annie join the pursuit at the studio, although Bruce reveals that he misled Otto by retaining the secret plans. Otto steals a truck to escape, and Rollo gives chase in a horse and carriage. As Otto discovers that the plans are not in the locket, Rollo’s carriage veers out of control and he crashes into the Wizard of Oz Emerald City entrance. When Rollo regains consciousness, he is back at the mission in Kansas, recovering from his fall. Rollo realizes it was all a dream, featuring his friends at the mission. They lead Rollo outside where Homer Henkel has arrived to take him to Hollywood as part of “Zeemeyer’s Midgets” acting troupe. Rollo boards the bus and meets “agent to the stars” Al Zeemeyer, who bears a striking resemblance to Otto Kriegling. As Rollo leaves for Hollywood, Henry Hudson raises a sign over the mission, renaming it the “Rainbow Mission.”