In Bavarian, "A gmahde Wiesn" means both "a mowed meadow" and colloquially "a project that cannot go wrong" - "a surefire thing". And "the Wiesn" is of course also a synonym for the Munich Oktoberfest, the largest folk festival in the world. There, as every year, showmen and Munich innkeepers gear up to compete for the coveted places. The violent death of the influential city councilor Hubert Serner (Bruno Graf) is therefore a topic in the city: Serner's maid Diana Aljescu (Anita Matija) found the lawyer in his garden pond. Serner, a member of the Economic Committee, had a say in the awarding of Wiesn licenses. He was a Bavarian-Baroque personality throughout his life.
His divorced wife Elizabeth (Sabine Bach) gives the Munich detectives Ivo Batic (Miroslav Nemec) and Franz Leitmayr (Udo Wachtveitl) the first clues. After the diligent research of their colleague Carlo Menzinger (Michael Fitz), the homicide detectives fight their way through an ever-growing list of Serner's beloved women. The statements of the interviewed women Ilsa Mischnik (Conny Glogger) and Hilde Gerbera (Claudia Wipplinger) are only partially helpful.
But how does the successor to the murder victim August Eckl (Philipp Sonntag) deal with the tangible economic interests of established Munich host families and showmen? On the one hand he has to deal with the resolute landlady Johanna Buck (Monika Baumgartner), who wants to add a garden to her already very lucrative Oktoberfest tent and is not the only reason why she quarrels with husband Niklas (Georg Maier) and daughter Evelin (Franziska Schlattner). . On the other hand, the innkeeper Xaver Neureuther (Fred Stillkrauth) and his son Timo (Joram Voelklein) fight for their place at the Wiesn.
The siblings Renee and Fridolin Zoll (Bettina Redlich & Michael Tregor) can be trusted with unthinking outbreaks of violence: the two showmen cherish and maintain the traditional carousel of their ancestors and face financial ruin with the beautiful but old ride if they do not get a permit for the Oktoberfest to get. During their investigations into this murder case, the Munich inspectors experience first-hand how the annual intrigues arise on the Theresienwiese around the construction of the Oktoberfest - until the mayor of the city finally calls out the redeeming words at the start of the Wiesn in the brimming beer tent: "O'zapft is !"