As "Vikings discover America" movies go, this is undoubtedly the best in a very small field (The other well-known entries include "The Norseman" with Lee Majors and the recent "Pathfinder"). It is certainly the one that makes the best effort at historical authenticity.
A band of Norsemen come to the new world for trade, bringing with them an Irish slave and his sister. The Irishman know how to find the sun on a cloudy day through the use of a crystal (the "Magic Stone") and thus is valuable. Dissension and hot blood among the Norsemen leads to conflict with the natives they had hoped to trade with, and the Irishman escapes and is adopted by the native tribe.
Some elements of the story are taken from Icelandic saga and other historical records, most notable an episode when the Norsemen are being attacked by the natives and are rallied by one of their women slapping a sword on her chest. The costumes and production design are about as historically accurate as one could possibly expect (at least there are no horned helmets).
The tone of the entire film is quiet, gentle, and family friendly. There is no sex or nudity, and the violence is acceptable for those concerned about small children who may be watching it. The leading actors are all young and appealing. If you are studying the history of the Vikings and their exploration of the New World or want to show something of what it might have been like, this is not a bad movie to watch.