Alex is a 12-year-old lad who is starting a new term at school and trying to adapt to his new surroundings. While hiding from bullies in a construction site, he finds a mysterious sword and discovers it's King Arthur's Excalibur. Eventually Alex meets legendary wizard Merlin and faces up to a tense battle with the evil Morgana. Joe Cornish's fantasy action adventure, starring Louis Ashbourne Serkis, Rebecca Ferguson and Tom Taylor.