In the year 355 Cologne is again on the world stage of history. Invasions of the Germanic tribes like the Alemanni and Franks shake the region, with Cologne as a Roman island in the midst of chaos. Rome’s power once again seems to wobble on the Rhine. If that were not enough, another usurper with the name of Silvanus (not related to the other Silvanus a few episodes before) in Cologne rises to become a counter-emperor. The “real” Roman emperor Constantius II then sends an undercover murder squad to the Rhine. Among them is the historian Ammianus Marcellinus, who experiences and reports everything at first hand. All this only happens in the year 355 and should lead to the greatest misfortune in the history of Cologne.