Complex sentence: Kurt is not fooled by Ed and Dexter's disguises and kidnaps them by sending them to Demented Hills Mental Hospital (run by a friend of Kurt's) to prevent the public from learning Mondo Burger's secret.
Split into simpler sentences: Kurt is not fooled by Ed and Dexter's disguises. He kidnaps them and send them to Demented Hills Mental Hospital to prevent the public from learning Mondo Burger's secret.