John Truscott goes to Borneo to work with the Iban. He reports to Henry Bullard, who gives him a "sleeping dictionary"--one of the locals who teaches him the local language and culture. And who he gives John is Selima. And while teaching him, John finds himself attracted to her. And we says it's not allowed, both the locals and Bullard forbid him to be in a relationship with Selima. But he defies them which has dire consequences.