Journey to the Center of Isabella (内部イザベラの胃！シマリスとChipettesを入力してください！Inside Isabella's stomach! Enter Chipmunks and Chipettes!) is the thirty-first episode of Hollywood World.
While acting, Isabella accidently swallows a shrunken submarine, with Katie, Sadie, May, Bridgette, Lindsay, Owen, Numbuh Four, Ash, Brock and Ben are in, so they have to find a way out. Also, they find 6 chipmunks in the submarine.