"Shōnen Santa no Daibōken" centers on a young boy named Santa, who embarks on a fantastical journey to save his village and uncover the mysteries of his world. The story begins in a small, snow-covered village where Santa lives with his adoptive family. The village is under threat from an ancient curse that brings perpetual winter, endangering its inhabitants and their way of life. Santa, driven by a sense of duty and curiosity, sets out to find the legendary "Eternal Flame," said to be the only force capable of breaking the curse.

Along the way, Santa encounters a diverse cast of characters, each with their own motivations and backstories. Among them is Lumi, a spirited girl with a mysterious connection to the Eternal Flame, and Frost, a rogue ice mage who initially opposes Santa but later becomes a reluctant ally. The group faces numerous challenges, including treacherous landscapes, mythical creatures, and the enigmatic "Winter Warlock," a powerful figure who seems to be orchestrating the curse for his own gain.

As the journey progresses, Santa learns more about his own origins, discovering that he is linked to an ancient prophecy foretelling the rise of a hero who will restore balance to the world. This revelation deepens the stakes, as Santa must not only save his village but also confront the larger forces threatening the entire realm. The narrative weaves together themes of courage, friendship, and self-discovery, with Santa's growth as a character serving as a central focus.

The plot is structured around a series of episodic adventures, each contributing to the overarching quest while introducing new challenges and allies. The pacing balances action-packed sequences with moments of introspection, allowing the characters to develop and the world to expand. By the climax, Santa and his companions confront the Winter Warlock in a final battle that tests their resolve and unity. The resolution ties together the narrative threads, offering a satisfying conclusion to Santa's journey while leaving room for potential future developments.