On the way to the Viking Fort Oak-Lynn Torgrim Nightwolf, his son Harald and Ornolf the Restless accidentally encounter a fishing boat. There is only one valuable thing on board, but what... The Crown of the Three Kingdoms of Ireland is a coveted trophy for local kings and invaders from the North. After all, its owner gains power over the whole country! But, having taken possession of the mysterious treasure, the Vikings do not even suspect how many tests it will bring them in the future...