A lecture in London about a mysterious, ancient crystal skull reminds Kirrily Haydon of a map her Australian grandfather had given her as a child, a map to find buried treasure, a crystal skull.

She had thought it a game, but was it? Now, decades later, her grandfather gives her a cryptic crossword and strange map to solve, again pointing to his 'treasure'.

Unravelling his clues, Kirrily and her companions find themselves among the sacred sites of Mexico, Peru, and England, and the great pyramids of Egypt.

Caught up in a world of ancient secrets and powerful sacred symbols, they discover primitive civilisations were not all they seemed to be.

As the team play the treasure trail like a computer game across Australia, the Americas, and Europe, they come across more than just buried treasure as they uncover for themselves other gems of the Universe an introduction to a spiritual and metaphysical world they never dreamed existed.