Cocaine with a pinch of cyanide salt is a deadly mixture: Alexander Haller experiences up close how banker Schachner collapses after a secretly drawn line. Although the blind inspector cannot see what is going on, he notices the typical bitter almond smell. Haller’s warning comes too late for his sister Sophie, who poisoned herself from mouth-to-mouth resuscitation. She fights for her life in the hospital. With the support of Commissioner Laura Janda, Haller begins to investigate. His nose leads him to a Fiaker business that delivers cocaine in Vienna. To find out whether the boss Laimer also supplied the murdered man, Haller’s driver Niko tries to infiltrate the dealer scene. He hires Alois Maxeiner’s family business as a coachman, whose daughter Therese works for the suspect Laimer. Schachner’s self-confident widow Solveig, the sole heir to his fortune, and the bank manager Dr. Hohmann target the investigators.