The Monster's Christmas 1981 ( 5.2)

On Christmas Eve, a nameless little girl reads 'The Monster's Christmas' storybook to her teddy bear, as something sneaks around in the trees outside her window. She hears a noise in the other room, and thinking that it's Father Christmas, she goes to investigate. She finds one of the monsters, who has come seeking help to defeat an evil witch that has stolen all the monsters' voices.