The Arthurian legend gets an inventive updating in this thrilling adventure that casts schoolchildren as latter-day Knights of the Round Table, destined to save the world. A 12-year-old boy (Louis Ashbourne Serkis) finds a sword stuck in a pile of rubble and pulls it out, unaware that the mythical Excalibur is now in his grasp, making him the new “king.”

The fabled wizard Merlin, a shapeshifter (Angus Imrie in one guise, Patrick Stewart in another), promptly appears and warns that an army must be raised since the lad’s success with the storied weapon has brought about the resurrection of the evil Morgana le Fay (Rebecca Ferguson).

Three schoolmates (Dean Chaumoo, Tom Taylor, Rhianna Dorris) agree to join the quest. Writer-director Joe Cornish serves up that treasured Hollywood rarity: an entertaining, family-friendly film that skillfully blends in strong messages, in this case about truth, justice and caring for others.

Potentially scary fantasy violence, two mild oaths. The Catholic News Service classification is A-II — adults and adolescents. The Motion Picture Association of America rating is PG — parental guidance suggested. Some material may not be suitable for children.