It was a simple no strings attached system. They weren't supposed to fall in love. That was the one rule they had for each other. (Stop at chapter 3 because currently being rewritten) Don't own South Park

Cartman, who has always been an unstable person throughout his childhood, is finally beginning to turn a new leaf with the encouragement of his recovering addict of a mother & his friends. But when someone figures out how to manipulate that dwindling instability and use it for their own gain, can Kyle Kenny and Stan help Cartman to fight back and take back control of his own mind?