Young Merlin is a teenager, discovering and then learning to master his gift for magic. Magister Caius, the learned court physician of king Uther Pendragon to whom he's assigned as humble page, teaches him medicine, coaches his magical self-study and warns for Uther's vicious aversion from magic. Merlin becomes squire to the noble but imprudent crown prince, Arthur, whose fate is linked with Merlin's.