Cartman gets AIDS due to an infected blood transfusion. Kyle laughs at the irony of the situation. Cartman, looking for revenge, decides to give Kyle AIDS.
Cartman learns that he has to have his tonsils taken out, at first he is reluctant but agrees when he is promised ice cream for after the surgery. He wakes up later in a hospital bed, the procedure over. Unfortunately, during the surgery the doctors at Hell's Pass Hospital accidentally gave him a blood transfusion using blood infected with HIV.
At South Park Elementary, the boys are briefed of Cartman's disease and that they should not treat him any different. Upon discovering this, Kyle finds this to be ironic (because of all the negativity Eric abused him with over the years) and even laughs about it, to the anger of Cartman.
Deciding to get revenge, Cartman (assisted by Butters) breaks into Kyle's house with a syringe of his HIV infected blood, and squirts it into Kyle's mouth, being asleep Kyle consumes it.
Upon taking a trip to Hell's Pass Hospital, Dr. Doctor informs Kyle and his mother that Kyle has HIV. Kyle almost immediately assumes he got infected deliberately from Cartman. Kyle then attacks Eric at school and starts a fight with him. The fight is broken up by Mr. Mackey. Principal Victoria makes Cartman apologize for giving Kyle HIV and then asks Kyle to apologize for being a "taddle-tale". Leaving the Principal's office, Cartman claims that they are even now, but Kyle does not agree and races to Cartman's house where he destroys Cartman's toys (such as pulling Clyde Frog's head off). Kyle is then about to break Cartman's Xbox 360 but Cartman convinces him to stop, telling him he knows how he can cure the virus. Intrigued yet still angered, Kyle listens to what Cartman has to say. Eric says that they should look into the case of former basketball player Magic Johnson, because he "has had AIDS for 50 years and he's still totally fine", according to Cartman. Kyle says that if Cartman is wrong, then he will break his Xbox.
Upon arriving at Magic Johnson's house, Kyle, Cartman and Magic look around to see what might cause his strong resistance to the virus. When they go into his bedroom, Kyle and Cartman are surprised to see that the room is full of cash. There are piles of money in obscure places such as the floor, such as on or under the bed. Magic explains to the boys that he doesn't trust banks, so he sleeps with all of his money. This is when they wonder if money might be the cure they were looking for.
The three of them then go to an AIDS research center. They decide to take a risk and have Kyle injected with vast amounts of money into his bloodstream. The experiment is completely successful, and so Cartman and Magic are cured as well.
The news breaks out that the cure for AIDS has been found; Kyle and Cartman are congratulated for it with a Jimmy Buffett concert, singing "Cureburger in Paradise". As the performance goes on, Kyle decides he is still going to break Cartman's Xbox, causing Cartman to run after him.