Hogfather

"From the imagination of the best-selling author Sir Terry Pratchett comes Hogfather, a magical and witty tale unlike anything you've seen before. It's the holiday of Hogswatch in the parallel universe of Discworld, the night when kids anticipate presents from the beloved Hogfather. But someone-or something-wants the Hogfather out of the way. Now' is up to the most unlikely of heroes to get the holiday back on track before humanity loses all hope.

Spoiler:

When the Hogfather was attacked, Death, like an expert mechanic hearing a change in the sound of an engine, had heard a harmonic change in the music of the universe. He was able to enter the congruent reality of the Hogfather in a way in which he could not enter the domain of the Tooth Fairy. Death applied first aid to sustain belief in the Hogfather among children, and recruited Susan, even Hex.

When Mr Teatime had failed, the Auditors attacked the Hogfather directly, in the form of hounds. It was necessary for Susan, as a human being, to be the one to act to save him. To do this she had to leave behind her inner babysitter, and be with her belief. It was not simple. At a point where the hog she was riding teetered on an icy ridge, precipitous drops on both sides, she repeated to herself, “He’ll catch me if I fall,” but an older voice within her said, “No, he won’t. If I fall now, I don’t deserve to be caught.” As in the case of Death and Miss Flitworth, an anthropomorphic personification was saved by the self-gift of a human being.

Later Susan said to Death, “The sun would have risen just the same, yes?” “The sun would not have risen,” he said. “A mere ball of flaming gas would have illuminated the world.” It would have been a world of oblivion.

The same human capacity to believe which supports the Tooth Fairy and the Hogfather creates the space for meanings such as justice, mercy and duty, which have no existence in the physical universe, to become. What Hogswatch seems to stand for is not that you will get presents if you have been nice, but that what you have done counts for something, and it is known. It matters. “All things strive...” says Hex. Strange though it may seem, given the general immersion of human and human-like beings in the mere business of staying alive, it is towards this point that all things strive. This very line also appears in Dwarf Lore.

Reference: https://wiki.lspace.org/Hogfather