Lars Lukas, a French swimmer, is shot after completing a cross-Channel swim from France. It appears to be a motiveless murder until Duval hears a tape recording of Lukas's last words, a lead to a smuggling ring.
Duval responds to a tip-off from an American reporter about a possible organised blackmail racket in a Swiss ski resort and goes to Switerland posing as his Paris banker friend, Count de Regny. When he arrives in Switzerland he realises that he has been set up as the next victim.
A policeman is shot in the back in the opal mining settlement of Cranby's Creek, in the Australian outback, and the townsfolk claim the shooting was carried out by Emil Brock, who is wanted for murder by Interpol.
Schroeder was erroneously convictd of the murder of his business partner, Kaltmann. Duval orders that the ex-convict be watched when he hints at committing the crime for which
he has already been punished.
Author Andrew Slater, writing a book about the war, discovers that Onno van Veer, remembered as a hero of the Dutch resistance, was not executed by the S.S. after all. Duval unearths a tale of treachery and murder.
Some conmen convince financial journalist Brownley that leading financier Untermeyer is dead. His report throws the stock market into confusion, alowing the conmen to clear up on the markets. Brownley is then murdered.