In medieval England, a young orphan named Arthur, commonly referred to as "Wart," accidentally stumbles upon the wizard Merlin, who resides in the forest. Recognizing potential in the boy, Merlin takes it upon himself to educate Wart in various subjects, primarily through magical means. With the companionship of Merlin’s wise but grumpy owl, Archimedes, Wart undergoes a series of enchanting transformations—becoming a fish, a squirrel, and a bird—to learn valuable life lessons about wit, bravery, and problem-solving. Merlin's unconventional teaching methods aim to prepare Wart for an important future that is, as yet, unknown to the boy.

Meanwhile, the kingdom of England is in turmoil following the death of its king, who left no heir. A mysterious sword embedded in an anvil appears in a churchyard, bearing an inscription that proclaims whomever can pull the sword from the stone is the rightful King of England. Wart's journey includes encountering various challenges and adversaries. His transformative experiences and newfound wisdom start to shape his character as he unwittingly inches closer to his destiny.