The team is assigned to recover the skull of the Mahdi, taken from the Sudan as a war trophy at the end of the 19th century. No one has any idea where the skull may be, but Chief Superintendent Boyd is told that returning the relic is key to peace in the Sudan. He's also asked to look into the death 20 years previously of a Sudanese refugee, Omar Jaffiri, as there is evidence that his death and the disappearance of the skull may be connected. Their investigation leads them to the Fakir Society, a hundred year old private club that has many secrets.
—garykmcd