An opium smuggling ring starts to operate across Europe, with its source in Turkey. Duval flies to Istanbul, where the local police have a suspect in the owner of an import-export business - except he appears to be operating quite legitimately. Finding a link in the supply chain gives Duval his first break, but leaves him with a problem: he must find a way of exposing the masterminds behind the scheme.
Journalist James Brownley arrives to interview noted businessman Baron Untermeyer, who wants the sensitive news of his retirement reported responsibly. The Baron dies in front of Brownley, who immediately reports the story causing a collapse in shares. The Baron was an imposter, though, and the death a fake, but Brownley himself is then found murdered. When Duval realises the nub of the fraud, not news the Baron was dead but the revelation he was still alive, investigating who profited from that knowledge leads back to the Baron's own private secretary, Castillon.
