Preparing for this expedition, Martin says his farewells, first in Switzerland, then back in Berlin, where he meets Sonia, then Bubnov, and then Darwin, who now works as a journalist. He tells Darwin the basics of his plan and enlists his assistance, giving him a series of four postcards to send his mother in Switzerland so she does not get suspicious. Darwin does not believe he is serious. Martin takes the train to Riga, planning to cross from there into the Soviet Union. After two weeks, Darwin gets nervous and follows his friend to Riga. However, Martin is nowhere to be found: he seems to have disappeared. Darwin takes his concerns to the Zilanovs, and then travels to Switzerland to inform Martin's mother of her son's disappearance. The novel ends with Martin's whereabouts unknown and Darwin leaving the Edelweisses' house in Switzerland having delivered the troubling news.