In Lisbon in 1904, a young man named Tomas discovers an old journal.  It hints at the existence of an extraordinary artefact that - if he can find it - would redefine history.

Traveling in one of Europe's earliest automobiles, he sets out in search of this strange treasure. Thirty-five years later, a Portuguese pathologist devoted to the murder mysteries of Agatha Christie finds himself at the centre of a mystery of his own and drawn into the consequences of Tomas' quest.

Fifty years on, a Canadian senator takes refuge in his ancestral village in northern Portugal, grieving the loss of his beloved wife. But he arrives with an unusual companion: a chimpanzee. And there the century-old quest will come to an unexpected conclusion.