Gwyn can feel danger coming in the wind. Somehow he knows the warnings have to do with the broken toy horse that holds the evil spirit of a prince who lived long ago. When Gwyn discovers that the prince's dark soul has escaped from the horse and is seeking revenge Gwyn, Emlyn, and Nia have to figure out how to save the mysterious soldier who claims to be Nia's distant cousin. With the help of the Snow Spider, can they recapture the prince's soul without hurting the Chestnut soldier?

Young magician Gywn and his friend Nia have been warned to stay away from Emlyn Llewelyn, the strange boy who claims his mother lives on the moon. And yet, a mysterious magic continues to draw them to him. But why? It's up to Gwyn and Nia to solve the mystery, with the help of Arianwen, the Snow Spider.

On his ninth birthday, young Gwyn (Osian Roberts), who lives on a remote hill farm in Wales, receives five strange gifts from his grandmother (Siân Phillips): a piece of seaweed, a yellow scarf, a tin whistle, a metal brooch and a small broken horse. Gwyn offers the brooch to the wind and receives back a tiny silvery spider - Arianwen, the snow spider - confirming that, as his grandmother had already guessed, he has inherited magical powers from his Celtic ancestor Gwydyon, a powerful magician whose exploits are described in the fourth book ("Math Son of Mathonwy") of the Mabinogion. With the help of the snow spider, Gwyn embarks on adventures involving other worlds of snow and silver, as he attempts to solve the five-year-old mystery of his sister Beth's disappearance in a snow storm.

An award-winning comedy set in a depressed town in the South Wales Valleys. When the local cinema is closed down, the former projectionist, plagued by money problems, devises an ingenious plan to make money.