Icebound - The Viking Cipher by Rick Spencer

The scientists who developed nuclear fusion inadvertently invented a science far more powerful and dangerous than nuclear weapons. Stunned and saddened by the use to which their initial work was put, they chose to keep their newest discovery a secret and away from military development. The secret location of that science can only be determined by decoding The Viking Cipher...and only one man can do it. But he cannot do it alone.