Question: What is the eighteenth season of the American animated sitcom which "The Cissy" is the third episode in 
Sentence (from "South Park (season 18)"): The season featured serial elements and recurring story lines, which "The A.V. Club" noted as an experimentation with episode-to-episode continuity, in which the episodes "explore the consequences of the boys' actions [week to week], allowing the plots to be motivated in part by their attempts to dig themselves out of a hole".
Relevant evidence: No