Red-headed Nariko's (voice of Anna Torv) clan is protecting the legendary "Heavenly Sword", a magical blade that has the power to slay the evil invading King Bohan (voice of Alfred Molina). When their village is attacked by Bohan's intimidating forces, which includes his gigantic mentally deficient son, Nariko's father gives her the sword for safekeeping. While she runs off with the sword he'll lead his people to safety. But she ends up confronting Bohan, who tells her, at length, that she has a brother she doesn't know about--and that he's the only one who can destroy him with the sword. He orders his warriors to kill her--she flees and jumps off a cliff. When she awakens she's at a campfire, fished out of the river by Kai, an orphan friend who had followed her. Kai reveals she's really Nariko's sister. So now the size of her family has doubled.
They continue on their journey to find the brother, protect a village along the way and go to rescue their father, who was captured and tortured by Bohan in his volcano perched castle. The women do indeed find the brother and give him the sword--but it doesn't go as planned.
I don't know how this film version compares to the video game franchise on which it's based--but it has some great visuals and plenty of violence. The animation doesn't compare to recent Hollywood fare but it's acceptable--and does emphasize the fact you're watching what's basically a video game. Recommended.