It is a dark time. For decades Hakon the Black, the most feared Norse Lord of the ninth century, has conducted bloody and gruesome raids throughout Europe, and laid his claim upon the seas. But it is also a time of hope. In the frozen wastelands of the north, Vidar searches for the Vestibule of Light. Alone, freezing and exhausted, he pushes on through the endless winter in the belief that once his quest is complete, he may return to the life he has left behind, and to Niclaus, the son he was forced to abandon. For Niclaus has a greater destiny - one foretold by Cado, the enigmatic Small Walker - and Vidar is but one player in the boy's life. Cado has enlisted the help of protectors from all corners of the Earth to shield Niclaus: men whose worlds are connected by only the loosest of threads. But as Niclaus becomes older, and the various worlds begin to converge, will Vidar and Cado have to make sacrifices beyond imagining to protect those they love.