Hermann Kappe's fourth case, summer 1916: The consequences of the First World War are becoming increasingly evident in the capital. The population is suffering from hunger, and almost daily, soldiers return from the front traumatized and severely wounded. The voices against the war are growing louder. In Berlin, two mysterious murders occur in succession, involving the colonial goods dealer Erich Röddelin and the lieutenant and factory director Arndt von Zabelsdorff, both killed with a hand grenade. However, Commissioner Hermann Kappe begins to doubt whether the confessing suspect is truly the perpetrator.