The boys are trying to buy an "nerection" for Kyle's dad to ask him what it is, but are kicked out of every shop. While walking down the street, Kenny suddenly catches fire and is reduced to a pile of ashes. The townsfolk witness this and recognize it as spontaneous combustion, prompting fear to spread in the town. After many more cases, the Mayor puts Randy Marsh in charge of finding out what is actually happening because he is the only scientist in town, even though he is a geologist.
At church, the town mourns over Kenny's death, burying what's left of his burnt-out coat. Afterwards, Priest Maxi tells the boys he hasn't seen them in church recently despite Kyle being Jewish. He then asks them to do the stations of the cross. Maxi insists that the combustion phenomenon is God's punishment for everyone's failure to attend Church regularly. While learning about the stations of the cross, the boys find out Jesus had a resurrection, which Kyle mistakes for "nerection". Cartman is made to play Jesus. After their performance they leave Cartman on the cross so he can get the "erection" which Kyle can give to his dad. Cartman desperately demands his friends let him down, but is left there for days.
Upon hearing that Kenny had been spending time with his girlfriend (introduced in the previous episode, "Rainforest Shmainforest") Randy finds out that the spontaneous combustion is caused by people not passing gas enough, and people with a boyfriend or girlfriend are the most likely victims because they are less flatulent than others. He advises the townsfolk to fart regularly. Everyone begins to do so and Randy is awarded and praised by the town. Unfortunately, the extreme amount of farts contributed to a hole in the ozone layer which begins to make the temperature rise drastically in the town. During this uproar, Kyle's dad finally gets the "nerection" Kyle had looked so hard for, having previously encountered some naked teenagers, so he goes to Sheila to "set things right". Kyle is glad that is off his chest, but once again forgets that Cartman is still waiting for his "nerection".
After becoming hated, Stan convinces Randy to work to find out how to stop it since he is now hated by all. He then explains that people need to fart, but in moderation. The town praises him once more. Meanwhile, Stan and Kyle remember that they had left Cartman on the cross and go to get him down. He has survived three weeks on his fat and is now incredibly thin. Infuriated that he has been left up there this long, he swears revenge on Stan and Kyle as soon as he gets down.