Plot
In South Park, Colorado, Stan Marsh, Kyle Broflovski and his adopted brother Ike, Eric Cartman, and Kenny McCormick visit the movie theater to see Terrance and Phillip's R-rated film, Asses of Fire, bribing a homeless man to help sneak them in. Due to the rampant profanity in the film, the boys begin swearing constantly. Their classmates also see the film, but Wendy Testaburger prefers to spend time with transfer student Gregory, to Stan's jealousy. The boys are sent to Mr. Mackey's office for swearing and are forbidden from seeing the film again by their parents, but still do so again later. Kenny attempts to imitate one of the scenes from the film by lighting his fart on fire, but accidentally immolates himself. He is rushed to the hospital and dies from a botched heart transplant, and the other boys are consequently grounded.
Kenny descends into Hell and encounters Satan and his abusive partner Saddam Hussein. With Asses of Fire becoming popular with children nationwide, the parents of South Park blame Terrance and Phillip's native Canada for corrupting them. Kyle's mother, Sheila, forms the Mothers Against Canada (M.A.C.) movement with other parents and later has a V-chip implanted in Cartman, causing him electric shocks whenever he attempts to swear. When M.A.C. arrests Terrance and Phillip, Canada bombs the Baldwin family in retaliation. The United States declares war on Canada and arranges to have Terrance and Phillip executed during a USO show within two days. In Hell, Kenny overhears Satan tell Saddam that Terrance and Phillip's deaths are the last sign of a prophecy of his invasion of Earth. After failing to persuade Satan to abandon Saddam, Kenny's ghost visits Cartman to warn him. Unable to reason with their mothers, Stan, Kyle, and Cartman form a resistance movement with their classmates to rescue Terrance and Phillip, recruiting the French-accented, misotheistic Cristophe, nicknamed "the Mole".
The boys infiltrate the USO show, where Stan and Kyle attempt to stall the execution and Cartman attempts to deactivate the alarm while the Mole prepares to free Terrance and Phillip. However, Kenny's ghost reappears before Cartman, who runs away in fear before shutting down the alarm, and the Mole is fatally mauled by guard dogs. The remaining boys try to warn their mothers about Satan's prophecy but are ignored, and Sheila orders the execution. The Canadian Army suddenly launches a surprise attack, resulting in a massive battle between the two armies. Cartman deactivates the electrical switch, allowing Terrance and Phillip to escape; the shock from the switch causes his V-chip to malfunction. Horrified at what they have incited, all the M.A.C. members except for Sheila decide to abandon their cause and search for their children. The children form a human shield to protect Terrance and Phillip from the United States Army as Kyle tries to reason with Sheila. While the army troops begin to back down, Sheila refuses and shoots Terrance and Phillip dead.
Satan's prophecy is fulfilled, and he and Saddam rise to Earth, but Saddam orders the soldiers of both armies to bow to him and browbeats Satan into letting him have power. After Cartman swears at Saddam, his malfunctioning V-chip produces an errant electric shock that strikes one of Satan's minions, and the boys urge Cartman to use it against Saddam. Saddam demands Satan assist him while insulting him, eventually causing Satan to snap and throw Saddam back into Hell, where he is impaled on a stalagmite. Grateful for Kenny's support, Satan grants him one wish, and Kenny wishes for everything to return to a pre-war state, though doing so means that he will remain in Hell. Kenny bids farewell to his friends and all of those killed in the battle are resurrected, including Terrance and Phillip. As the Americans and Canadians make peace, Sheila reconciles with Kyle, as does Wendy with Stan. For his sacrifice, Kenny is allowed to enter Heaven.
