As a result of the Berlin Conference of 1884-1885, the Congo Basin is claimed by King Leopold II of the Belgians, who rules the Congo Free State in personal union with the History of Belgium#Empire. The country is on the verge of bankruptcy, Leopold having borrowed huge amounts of money to finance the construction of Rail transport in the Democratic Republic of the Congo and other infrastructure projects. He sends his envoy Léon Rom (Christoph Waltz) to secure the fabled diamonds of Opar (fictional city). Rom's expedition is ambushed and massacred. A tribal leader, Chief Mbonga (Djimon Hounsou), offers Rom the diamonds in exchange for an old enemy: Tarzan.