God of Thunder (Rogue Angel #7)

Archaeologist Annja Creed narrowly escapes an attack by unknown figures when she tries to collect a package near her loft. She later learns that the sender--an old colleague named Fellini--has been brutally murdered. Fellini had been researching the Hammer of Thor, the Norse god of thunder, and had linked it to a Viking warrior and a twelfth-century Latvian village. A coded message in Fellini's package leads Annja on a wild chase along the canals of Venice to Latvia for more clues to an ancient treasure. Rumored to be hidden deep in the forests of Latvia for nine hundred years, this fabled prize is also sought by a ruthless corps of mercenaries. And they will do anything to find it. Including killing Annja Creed.