After a series of deadly museum robberies, where cultural treasures of Viking origin are stolen, historian Dr. Nina Gould is intrigued and infuriated. She elicits help from her friend, investigative journalist Sam Cleave, to see if they can discover and expose the culprits. Nina thinks that she may have befriended one of the robbers involved, and so begins the chase to uncover the truth. However, Nina has no idea that in doing so she will discover a secret war waged by ancient societies under the very nose of the modern world.

Involving Sam in her search, the two of them find that the Order of the Black Sun is actively in pursuit of one of Norse Mythology's greatest legends - Valhalla. Believed to be the prison of an ancient evil which could help the Nazi's rule the world, Valhalla becomes the focal point of Lita Røderic, a nefarious Aryan villain unmatched in mind or means.

Nina and Sam become involved with The Brotherhood, an ancient order of warriors sworn to protect the secret location of Valhalla. They realize that the relic the robbers sought is a vial containing an elixir of second sight, a precious key to the location of the earthly Hall of the Slain which Nina is entrusted with. However, when Sam inadvertently drinks the elixir, giving him visions of where Valhalla lies, he is thrust into the world of The Brotherhood along with Nina.

Now they are locked in a deadly race to find Odin's Hall before the Nazi's claim the powerful weapon within and destroy the free world to usher in the Master Race. Will Sam and Nina survive the perilous quest against the terrible Lita Røderic in her pursuit of world domination? Does Valhalla even exist? And if so, what lies inside that would bring about Ragnarok?

With the modern world in ignorant bliss, only The Brotherhood, the relentless knights of the Hammer, can save it from the dreadful fate of ultimate Nazi domination.