Commissioner Hermann Kappe reunites with his former school friend Traugott Lempel in May 1942 and witnesses a mysterious death in Lempel's office at Rheinmetall-Borsig: a man suddenly falls from a window on the third floor. Was it suicide, an accident, or murder? Kappe immediately begins his investigation but is soon called off from above. However, he suspects a connection between the deceased at Borsig and the disappearance of a young man whom Lempel is worried about. Thus, he continues to investigate and soon uncovers evidence of mysterious financial transactions involving high-ranking Nazi officials. Should Kappe steer clear of everything or attempt to uncover the truth, putting himself in danger? It Happened in Berlin, the grand chain novel about Commissioner Hermann Kappe, reflects the Berlin of the 20th century through fictional criminal cases.