In a luxury hotel on Lake Zurich, one of Fantin-Latour's famous dahlia paintings is stolen. The eccentric owner and hotel heiress Dahlia Gutbauer hires Johann Friedrich von Allmen, of all people, to recover the work of art. While Allmen accepts the lucrative assignment with interest, his servant Carlos suspects that this investigation is far too dangerous, since a security guard and a hotel guest have already been murdered in connection with the theft. Of course, bon vivant Allmen throws the well-intentioned warning to the wind, but soon the smart, self-proclaimed art detective has to compete with ice-cold opponents who are not to be underestimated.