In a Stockholm museum, thieves steal an enormous Norse runestone, but not before killing a security guard. When Nina Wilde, head of the International Heritage Agency (IHA), and her husband, ex-mercenary Eddie Chase, arrive to investigate, they are told a chilling story: A scholar has discovered that the stone may be one of two keys to finding the mythological site of Valhalla, where the Vikings predicted the world's final battle would begin. The second stone lies at the bottom of a Norwegian lake. But when Nina and Eddie race to the scene, they're hit with a shocking surprise. Covert agents from around the world, including a ruthless mole in the IHA, are drawn into a lethal game. Then a disturbing secret surfaces from Eddie's past, involving a mission in Vietnam and a woman he tried to save. Suddenly suspicious of her own husband, Nina cannot afford to stop the perilous search for the artifact. For somewhere in a remote wilderness, two forces are about to converge: one that could save the world . . . and one that could destroy it.