When Professor Lloyd Marsden is found murdered in the Museum of Victoria, Special Detective Sam Diamond is assigned to catch the killer. Thrown into a world of obsessive collectors, strange poisons, funerary rites and ancient artefacts, Sam's photographic memory and cryptic crossword skills are invaluable tools in her investigation.

But when archaeologist Dr Maggie Tremaine whisks her halfway round the world in pursuit of the truth, Sam finds way more questions than answers. From Australia to Egypt to Peru, Sam and Maggie hunt down the clues to a strange pact and a legendary relic.