In Würzburg, during repair work on a pillar of the Old Main Bridge, a human skeleton is discovered. A few days later, prominent citizens begin to disappear in the Main metropolis. When one of them is found dead under mysterious circumstances, Erich Rottmann gets involved in the investigation. Is a serial killer on the loose in Würzburg? And what does all of this have to do with the former mayor? The retired commissioner and his dog Öchsle find themselves in great danger during their inquiries and ultimately rescue the mayor from an extremely difficult coalition.