Thirteenth book in the Cairo Jim fantasy/adventure series for children. Jim and friends are sent to Rome to get to the bottom of the disappearance of Emperor Tiberius' priceless and mysterious artefact - the Imperishable Bauble. They soon realise the bauble holds a terrifying power that could wipe out civilisation. Previous titles include 'Cairo Jim and Doris in Search of Martenarten' and 'Cairo Jim on the Trail to Cha Cha Muchos'.