This historical fantasy show is based on the best-selling novel The Saxon Stories, a story set during the Viking / Dane invasion of Britain.
Uhtred was a small boy when he was kidnapped and then raised by the Danes. When he unexpectedly gets caught up in the conflict, his half-Saxon half-Dane mix makes at the same time valuable and untrustworthy for both sides.
There has never been a better alternative to Game of Thrones. The great writing and great performances from a cast of newcomers inevitably induce the same sense of addiction.