When Greg Amundsen and his three friends discover a hidden cavern in the Norwegian wilds, they think they've made the find of the century. An ancient stone city. A tomb full of treasure.

But then their nightmare begins. A strange illness strikes. A ghostly Viking terrorizes them. They are trapped underground, held by a mystical ward that, instead of keeping people out, keeps them in.

The clock is ticking. Surrounded by the darkest side of the ancient Norse, four typical contemporary teenagers must overcome timeless horrors -- or never see sunlight again.