On 13 December 1941, on California’s Pacific coast, a nude swimmer grabs onto the periscope of a Japanese submarine as it rises from the water. Commander Mitamura, German officer Von Kleinschmidt, and several Japanese sailors emerge from the hatch without seeing the woman perched above them. Mitamura wants to demoralize Americans by attacking Hollywood, but does not know his location because his compass stopped working. Meanwhile, in the Los Angeles kitchen of Malcolmb’s Café, fry cook Wally practices his “jitterbug” dance steps as he wiggles into the dining area to serve coffee to U.S. soldiers Sergeant Frank Tree, Corporal Chuck “Stretch” Sitarski, and Private First Class Foley. Sitarski is insulted by Wally’s “Pearl Harbor” Hawaiian shirt, due to the Japanese attack on the U.S. Navy base a week earlier. A fight ensues, and when the soldiers leave, the owner fires Wally and his co-worker, Dennis. At the Crystal Ballroom, Miss Fitzroy teaches her new United Service Organization (USO) hostesses, including Betty Douglas and Maxine, how to behave at the dance that night. Betty is distressed because she wants to dance with Wally, but civilian males are not allowed to attend. Elsewhere, Wally tries on a “Zoot” suit at a department store, as Dennis sneaks in with a hand-cranked air raid siren. Shoppers are already nervous because of news reports about a possible Japanese invasion, so when Dennis sounds the siren, customers and employees run, while Wally walks out wearing the Zoot suit. Meanwhile, in Death Valley, U.S. Army Air Corps pilot Captain Wild Bill Kelso lands his airplane at a highway gas station market. When he disembarks, the airplane drifts away from the pump, spilling gasoline, and Kelso accidentally blows up the station while chasing after his plane. At Daugherty Field in Long Beach, Major General Joseph W. Stilwell ignores intelligence warnings from his secretary, Donna Stratton, that city reservoirs are in danger of sabotage, and disregards a telegram from Colonel “Madman” Maddox stating that the Japanese have a hidden airfield near Pomona. Stilwell’s aide, Captain Loomis Birkhead, tries to rekindle a relationship with Donna Stratton, luring her into a P-17 bomber and nearly seducing her in the cockpit. Loomis accidentally drops a bomb onto the tarmac, which explodes a short distance from General Stilwell as he addresses the press. Meanwhile, Betty and Maxine return to the Douglas’s seaside family home in Santa Monica, and find Wally hiding in the garage. Maxine informs him that they can only dance with servicemen at the ballroom, adding that he would never be admitted wearing his Zoot suit. Sgt. Frank Tree’s motor pool crew arrives at the Douglas house, places an anti-aircraft gun on the front lawn overlooking the ocean, and assures them that a gun crew will arrive later. Cpl. Sitarski tries to seduce Betty, but finds Wally in the garage, and tosses him into a trash truck. As he is driven away, Wally shouts that he will meet Betty at the USO dance at 8:00. Next door, Civil Defense guard Angelo Scioli designates Claude Crumm and Herbie Kaziminsky as enemy aircraft spotters on the Ferris wheel at the nearby Ocean Amusement Park. Cdr. Mitamura sends Japanese sailors ashore to determine their position, and they kidnap Christmas tree salesman Hollis “Holly” Wood, thinking the sign on his property says “Hollywood.” Hollis refuses to tell Mitamura where Hollywood is, and when a sailor finds a toy compass prize inside the American’s box of candy-popcorn, Hollis swallows it. The sailors pour prune juice down his throat and wait for him to pass the compass, but Hollis escapes. At Ocean Amusement Park, Herbie, his ventriloquist dummy, and Claude sit atop the motionless Ferris wheel, watching for airplanes. In Hollywood, Stilwell gets a message from Col. Madman Maddox that Japanese troops are parachuting into Barstow. Loomis Birkhead convinces the general to let him drive to Barstow and make certain the crazed colonel does not commandeer airplanes. At the mention of airplanes, Donna Stratton volunteers to accompany him. Gen. Stilwell relaxes by watching Dumbo, a Walt Disney animated movie, at a Hollywood Boulevard theater. Across the street, Wally tries to get into the USO dance, but falls into the hands of Cpl. Sitarski, who is “absent without leave” (AWOL). Sitarski sets Wally’s Zoot suit on fire and drags Betty into the ballroom. On the submarine, Japanese sailors hear a radio broadcast of the USO show, and Mitamura locks on the signal to determine Hollywood’s coordinates. Meanwhile, Wally steals an unconscious Navy Shore Patrol sailor’s uniform and enters the dance. As Wally jitterbugs with Betty, Sitarski and the angry, half-nude Shore Patrol sailor beat him unconscious, sparking a brawl. At their barracks, Sgt. Tree’s men are given an assignment to drive a tank into Hollywood. In Barstow, Loomis and Donna look for airplanes, and Madman Maddox informs them he has only an old trainer aircraft with no radio. Loomis and Donna board the plane, and as it becomes airborne, Donna becomes sexually aroused. Maddox sends Wild Bill Kelso in pursuit of Loomis to find the purported Japanese airfield. Meanwhile, Loomis’s radio cannot receive calls from suspicious Civil Defense authorities, who react by contacting “Interceptor Command.” In Hollywood, Sgt. Tree and his soldiers arrive at the USO ballroom riot in a tank, where he tries to calm everyone with a patriotic speech. Meanwhile, Interceptor Command puts the American military on “Condition Red” alert, and sirens are heard around the city. In Santa Monica, Ward Douglas spots Mitamura’s Japanese submarine through his binoculars. Gen. Stilwell exits the movie theater and takes command. As Loomis and Donna make love while flying over Hollywood, anti-aircraft guns open fire. At the ballroom, Wally awakens, grabs an Army jacket, and searches for Betty, but Tree mistakes him for a sergeant and commandeers him for emergency duty. Tree is accidentally knocked unconscious in the melee, and Wally takes over the tank unit. In the air, Wild Bill Kelso chases Loomis and forces him to crash-land in the La Brea Tar Pits. Elsewhere, Ward Douglas and Angelo Scioli take control of the abandoned anti-aircraft gun. On the Ferris wheel, Claude and Herbie see the submarine, as does Wild Bill Kelso. Mistaking Kelso for an enemy pilot, Herbie fires his rifle and sets the plane on fire. Back in Hollywood, Sitarski forces himself upon Betty, until Wally knocks out the rogue soldier and embraces her with a kiss. Wild Bill Kelso crash-lands his airplane on Hollywood Boulevard and warns Wally that a Japanese submarine is anchored off the coast at Ocean Amusement Park. Wally, Dennis, Betty, and the tank crew head toward Santa Monica, and Wild Bill follows on a stolen motorcycle. When Ward fires the anti-aircraft gun at the submarine, he mistakenly shoots a hole through his own house. Angelo sends one of Ward’s boys with a key to activate the Ferris wheel and rescue Claude and Herbie, but the lad pulls the master switch instead and lights up the amusement park. Thinking he has finally found Hollywood, Mitamura opens fire on the park and deploys a torpedo that knocks the Ferris wheel off its supports. The big wheel rolls down a pier and falls into the ocean, just as Wally, Betty, and the soldiers arrive in the tank. Wally takes the vehicle to the end of the pier, and Wild Bill Kelso roars past on the motorcycle, plummeting into the water. As Cdr. Mitamura prepares to submerge, Wild Bill climbs aboard and order the Japanese to take him to Tokyo. In the morning, everyone recuperates at the destroyed Douglas house, and Gen. Stilwell commends the civilians for sinking the submarine. As Ward hangs a Christmas wreath on his door, the house slides over the cliff into the ocean. Gen. Stilwell predicts a long war.