"Probably" is the tenth episode of Season Four, and the 58th overall episode of South Park. It aired on July 26, 2000.
Cartman preaches and the children begin plans to build a church. Satan spends the night with Saddam Hussein. Kenny wasn't killed in the previous episode, but the bus that ran him over stops in Mexico, which is pretty much the same as Hell. Satan, in his time of crisis, turns to God for advice. Cartman is discovered as a fraud and is sent to Mexico as punishment.
In this episode, the South Park children build a church to live in sinlessness, and do not go to school, avoid home as much as possible, and listen earnestly to Cartman, who acts like a televangelist-esque preacher. Meanwhile, Kenny calls from Ensenada, Mexico (about 60 miles (95 km) south of Tijuana on the Baja California peninsula) where the bus he was run over by dragged him and which he thinks is hell, and tells about the "Underworld" for Cartman's sermons: "that everyone in Hell speaks Spanish, that in Hell there is water, but if you drink it you will bleed out your ass for seven hours, and there are a lot of trinket stores that all sell the same trinkets."
Meanwhile, in the real Hell, Satan sleeps with Saddam. He then tells Chris about what happened. Chris forgives Satan, which actually upsets Satan more. Satan screams at Chris saying that he wishes that he would at least be angry at what happened. Then, Chris and Saddam keep getting into fights, which lead to the two murdering each other; nevertheless, they keep reappearing in Hell to kill each other again. Satan constantly debates whether he should be with Saddam, whom he finds sexually attractive, or Chris, who is kinder. Meanwhile in Hell, Satan asks JonBenét Ramsey for help regarding his two lovers. She suggests he ask God for help.
Satan goes and sees God in Heaven (which is occupied solely by Mormons); God calls Satan a pussy himself for complaining about such a problem, saying to him, "You got kicked out of here for being a headstrong rebel. And now you're a whiny little bitch." God further tells Satan that he should dump them both and try to learn to appreciate himself before he tries to find a relationship.
Back in South Park, Cartman reveals to Stan and Kyle that he, in fact, only opened the church to con kids out of money, and not out of religious fervor (according to him, people can easily be forgiven by God). Sister Anne then manages to disband Cartman's church by having Jesus come and close it. As punishment for his sins, Cartman is sent somewhere worse than Hell, Mexico, and happens to meet Kenny at the bus stop. A similar event happens in Hell, when even after Satan explains his intent to be single, Saddam continues to harass him, the Devil reveals that he has "asked an old friend for a favor", and Saddam is forced to go live up in Heaven with the Mormons. This, to him, is Hell.