his series finds Stan, Kyle, Cartman, Kenny, Butters and co getting into fixes through their usual blend of innocence and mischievousness. As well as coming to terms with the perils of social networking and being accused of sex addiction in the furore that sweeps the nation in the wake of the revelations surrounding Tiger Woods, the boys finally reveal the identity of the suitably mysterious Mysterion in a three-part special.

Overview from themoviedb.org