The ultimate duo — Nina Wilde and Eddie Chase — return in their ninth action-packed adventure. Secrets from the past emerge to threaten archaeologist Nina Wilde and her husband, former SAS soldier Eddie Chase, when a Viking runestone is stolen by a murderous gang of raiders. The stone holds the key to an ancient evil concealed in one of Norse mythology's holiest places: Valhalla. Travelling to Sweden, Eddie and Nina find themselves in a race against time to locate the legendary hall of the Viking warriors — before rival powers claim its deadly contents for themselves. It is a quest that will force Eddie to revisit a dark chapter from his mercenary days that he has kept hidden from everyone... including his wife. Only Nina and Eddie can prevent the unleashing of a primordial terror from the depths of the earth. But even if they succeed, will the cost be greater than either of them could have ever imagined...