Buster Moon and his musically gifted friends must persuade the reclusive rock star Clay Calloway to join them for the opening of their new show.

Old-school magic meets the modern world when young Alex stumbles upon the mythical sword Excalibur. He soon unites his friends and enemies, and they become knights who join forces with the legendary wizard Merlin. Together, they must save mankind from the wicked enchantress Morgana and her army of supernatural warriors.