Flavia and her friends are on a quest for the Emperor Titus - to steal a valuable gemstone known as 'Nero's Eye'.The Delphic Oracle prophesied that whoever owns the gem will rule Rome - so Titus is determined to claim it for himself.Their travels take them across the Roman province of Mauretania, from Sabratha (in modern Libya) to Volubilis (Morocco).As they travel on a caravan across the desert they encounter slave-traders, pantomime actors and a wild animal stampede.The detectives must consider another quest: what has happened to Uncle Gaius?Meanwhile, Flavia faces some tough decisions about her future.