The movie begins in Southern England in the Middle Ages and then six knights are seen riding in horses towards a destroyed town. They see the remains of burned buildings and dead people until they come upon a mother and her dead baby. She quickly dies and then a rhino-sized dragon flies overhead, the knights follow right behind, vowing to kill the creature.
The King has sent his best Knights to defeat the Dragon besieging his castle. Along their epic adventure they encounter malicious sirens, warrior women on a mission of revenge and an unstoppable army of the undead.