Progress is not always a panacea, and sometimes, if the principles that unite man with nature are not respected, it can become dangerous. The internationally renowned scientist, Don Fernando Salazar, returns to his hometown with his daughter to launch his most ambitious project: the construction of a hydroelectric power plant. This will cause a series of tensions among the inhabitants of the small village, especially between an old charcoal burner and the scientist. The small village nestled in the Pyrenees will experience a series of extraordinary events following the intervention of a mysterious and magical character, Olentzero, who, together with the charcoal burner's grandson, will star in an adventure they will never forget.