Alma Täuber investigates between illustrious spa guests and illegal casinos – the first case for the telephonist.
Baden-Baden, 1922. Telephonist Alma Täuber loves her work, which she masters through skill and energy. Together with her best friend Emmi, she enjoys being free and carefree, and leading a self-determined life.
When Alma happens to overhear part of a conversation while connecting a call, she is captivated by the voice of the caller, who speaks of a job carried out 'in the colonnades'. Alma looks into the matter and discovers that a woman has been found murdered there. But the police do not believe that there is any connection between the murder and the call - apart from Inspector Ludwig Schiller.
Bold and decisive, Alma does not allow herself to be sidetracked and, together with Schiller, she moves between fashionable spa hotels and illegal casinos in search of the murderer.