The South Park kids become even bigger potty mouths because of a Terrence and Phillip movie (Asses of Fire).
The parents, led by Kyle's Mother, have Terrence and Phillip arrested. This starts a war with Canada which fulfills a prophecy involving the blood of Terrence and Phillip touching U.S. soil. If this happens, Satan (and his lover Saddam Hussein) will rule the earth.
Things literally go to Hell and we learn that Saddam wants to rule the world by himself and doesn't really love Satan. Encouraged by Kenny (Kenny died earlier and went to Hell despite the efforts of his Doctor, George Clooney) Satan asserts himself and gets rid of Saddam.
Satan then gives Kenny one wish. Looking around at all the death and destruction of the war, Kenny asks for things to be like they were before the war started, despite the fact that his wish will not bring him back to life. After Kenny's wish is granted, we finally see Kenny without his hood, showing us that he has the face and voice of an angel. Happily, Kenny is taken into heaven because of his selfless sacrifice.
Thanks Don P!