On their way to entertain the troops in wartorn Guam, Duke Mitchell and Sammy Petrillo fall out of their plane and land, unconscious, on a South Pacific island called Kola Kola. Local tribesmen bring the men to the main village, where Chief Rakos' daughter Nona saves them from beheading and instead has them laid out in a tent. When they finally wake, unhurt, Nona explains where they are and invites them to a luau that evening in their honor. At the dinner, Sammy grumbles at Duke and Nona's romantic coupling, but then is even more horrified after Nona introduces him to her overweight, aggressive sister Salome. Salome chases Sammy to the center of the luau, where he performs jokes, and Duke croons. Afterward, during a moonlit walk, Nona informs Duke that she was educated in America because she will one day be the queen of her island. Duke needs desperately to reach Guam, so the next day, Nona brings the Americans to meet her boss, scientist Dr. Zabor. Zabor, who conducts evolutionary experiments on monkeys, suffers from his unrequited love for Nona. Although Sammy immediately notes the scientist's resemblance to Dracula and his home's castle-like appearance, he and Duke nonetheless accept Dr. Zabor's offer to board with him. Local lawman Pepe Bordo, who owns the island's only wireless radio, then visits and promises to try to find a ship that can take them as passengers. Nona grows upset at the thought of Duke leaving, and Duke kisses her comfortingly. That night, Dr Zabor's chimpanzee, Ramona, breaks out of her cage and climbs into bed with Sammy, and when he returns her, he rocks her to sleep. Days later, the chief invites everyone to dinner. Dr. Zabor brings his large assistant, Chula, and watches Duke and Nona jealously. When they leave together mysteriously, he has Chula follow them, and the assistant hears Duke ask Nona to marry him. That night, Dr. Zabor works on a potion and injects it into Ramona, who turns into a little spider monkey. By morning, however, she is a chimp again, and Dr. Zabor refines the potion to strengthen it. When Duke leaves to visit Pepe, Chula follows and knocks him out. He brings the singer back to the lab, where Dr. Zabor injects him with the new potion. Nona and Sammy soon search for Duke but, not finding him, send Nona's warriors to look for him. Meanwhile, Duke has become a huge gorilla, and Dr. Zabor exults at the thought that Nona will no longer love him. The scientist lies that the gorilla is Ramona, and Sammy tries to play with it. Duke frantically attempts to communicate via hand signals, but Sammy fails to understand him until he sees the real Ramona playing outside and then hears Duke sing. Finally, he unlocks Duke and the two escape the castle. Although Duke is detained in the jungle by an amorous female gorilla, the two friends make it to Nona's village, where she is crying. Sammy explains the situation to her and just as she embraces Duke, Dr. Zabor appears behind them with a rifle, claiming that the gorilla is deadly and must be shot. Sammy jumps in front of Duke at the same time that Dr. Zabor fires, and is shot. Suddenly, Sammy is shaken by Duke, and realizes that the whole island adventure has been a dream and they are in their dressing room at the Jungle Hut nightclub in New Jersey. As they walk onto the stage, Sammy recognizes all of the club employees as figures from his dream. He almost runs when he sees Salome, who is now a dancer in a Hawaiian skit, but once she wraps him in a kiss, he suddenly does not want to stop. Duke pulls Sammy onstage, where they perform their routine to enthusiastic applause.