Mr. Mackey introduces Al Gore, who takes the assembly at South Park Elementary and warns the students about ManBearPig, a ferocious beast and menace to mankind. Unfortunately for him, nobody takes him seriously.
Al Gore meets Stan, Kyle, Cartman, and Kenny as they play basketball. Dressed as ManBearPig, he fails to scare the boys yet warns them that next time it could be the real ManBearPig. He gets them to sign his ManBearPig awareness sheet and take a bumper stick explaining how everyone must stop Manbearpig. Randy stops by in his car and offers the boys a ride home. In the car, he tells them they shouldn't hang around with Al Gore and that there is no ManBearPig - Al Gore simply wants attention.
Stan is awoken in the night by a phone call from Al Gore, who asks him and his friends to attend a ManBearPig meeting the following morning. Stan tries to tell Al Gore that he has school the next day and cannot attend, but Al Gore exclaims that Stan doesn't believe him. Feeling sorry for him, Stan says he's just scared he can't do anything to stop ManBearPig and that he'll attend.
The next day, Cartman, Kyle, and Kenny question why they have to go to the meeting. Stan explains he feels sorry for Al Gore.
Stan tells Al Gore that his dad is a geologist, and how he thinks ManBearPig isn't in the area. After telling Al Gore his dad doesn't have hooves he and the others prepare to leave. Just then, Al Gore detects something on his navigation screen in the Cave of the Winds, believing it to be ManBearPig. The boys say they have school, but their minds quickly change upon hearing Al Gore can get them all excused from class.
In the Cave of the Winds, Al Gore gets the boys to look for ManBearPig droppings which he explains are just like pig droppings but more manbear like. As they explore, Al Gore mistakes the sound of the wind (which the cave is named after) to be ManBearPig. He quickly gets out his gun and begins to shoot the walls. The rocks crumble down and trap the boys.
Discovering their dilemma, the boys search for a way out. Cartman meanwhile finds what appears to be treasure. The boys realize the only way out is up a steep path, so they decide to stay put. Determined to keep the treasure for himself, he begins to consume it. The boys notice him putting on weight, and believe him to be ill.
Al Gore tells the rescue team who are trying to save the boys that they need to flood the cave with molten lead. The rescue worker explains that they can't because it will kill the boys. While discussing the digging plan, they explain they will be digging to an area called "Smuggler's Den", a place where children can have their photo taken with fake treasure.
Al Gore meanwhile, decides to flood the cave by diverting a stream.
The boys realize the cave is being flooded, and attempt to escape. Unfortunately, Kyle has to swim to safety with incredibly bloated Cartman leaning on him.
Outside, the rescue team seems content that nothing could have survived the flood, and Al Gore quietly celebrates believing that he has "killed ManBearPig once and for all".
While holding a memorial service for the boys, they show up and Al Gore explains he has saved them. Stan finally tells him however that he was only nice to him because he felt sorry for him and calls him a loser. Al Gore replies that the guy who stopped ManBearPig alone is hardly a loser. Just then, Cartman craps out all the treasure, but is disappointed to hear it's all worth about $14. Kyle becomes upset and begins lecturing Cartman because he had to carry him after he ate the fake treasure. Al Gore then explains he should make a movie about himself. Having donned a cape he attempts to fly away. Cartman then craps out a golden vase.