Claus begins life as a human infant discovered abandoned near the Forest of Burzee by Ak, the Master Woodsman of the World. Ak entrusts the child first to the lioness Shiegra, but the wood nymph Necile adopts him, raising him among the immortal inhabitants of Burzee. Growing up there, he forms a close childhood bond with Mary, who tends the forest flowers; her precise nature as a fairy, ryl, or wood-nymph remains unspecified. Claus visibly differs from the immortals, who can fly, while he remains earthbound. The forest animals, including an owl, bear, leopard, squirrels, and rabbits, speak and interact with him.

Upon reaching maturity, Claus leaves Burzee to establish his home in the nearby Laughing Valley, seeking closer proximity to human society. There, he befriends a young human girl named May, who frequently visits. Driven by compassion for all children, Claus crafts toys as gifts to bring them joy. This mission draws opposition from malevolent forces, particularly the Awgwas, who steal the toys to prevent children from behaving well. These conflicts escalate into battles where the immortals of Burzee, including Zurline, Peter Knook, Flossie, Glossie, and Blinkie, rally to defend Claus and his cause against the Awgwas and their allies.

Claus faces episodic challenges testing his resolve and ingenuity. He rescues Blinkie from peril, devises strategies to outmaneuver threats like goblins in Ghost Valley, and encounters a man who might be his biological father, complicating his understanding of his origins. Further trials involve protecting companions, such as preventing a wealthy child from purchasing Blinkie, and navigating encounters like accidentally disrupting Mary's floral work, leading to an encounter with a Gadgol.

His evolution into the iconic gift-giver includes adopting nocturnal deliveries via chimney when doors are locked, a method necessitated by Awgwa interference. The reindeer Glossie and Flossie become integral to his journeys, pulling his sleigh. The narrative culminates in his transition to the immortal figure Santa Claus, recognized for delivering presents and inspiring traditions like placing gifts in stockings or on trees for those without chimneys. The final episodes depict his formal recognition as Santa Claus and a farewell to his earlier life, solidifying his legendary status.