The Mask of Atreus:

An obscure museum's dead proprietor lies in a secret room surrounded by one of the world's most astonishing collections of Greek antiquities. Only a priceless Mycenaean death mask has been taken, along with the bones of a legendary hero thought to exist only in ancient myth. Looted by the Nazis, the treasures are still being sought by those whose dreams of glory remain undefeated.

The mask is an unparalleled discovery that will be a force for devastating retribution in the wrong hands. But by the time museum curator Deborah Miller learns the truth, it may be too late not only to save herself--but to reveal to the world the awesome secret she's uncovered.