Mog feels a little ignored during the Thomas family's Christmas preparations. When she spots the huge Christmas tree, she freaks out and climbs to the roof, where she refuses to move no matter how hard the family tries.
| Actor | Role |
|---|---|
 Adjoa AndohNarrator (voice) | Narrator (voice) |
 Benedict CumberbatchMr. Thomas (voice) | Mr. Thomas (voice) |
 Claire FoyMrs. Thomas (voice) | Mrs. Thomas (voice) |
 Miriam MargolyesAunt One (voice) | Aunt One (voice) |
 Maggie SteedAunt Two (voice) | Aunt Two (voice) |
| CCharlie HigsonJolly Uncle (voice) | Jolly Uncle (voice) |
 Zawe AshtonMrs. Gaynor (voice) | Mrs. Gaynor (voice) |
 Gareth BerlinerChestnut Seller (voice) | Chestnut Seller (voice) |
| AAmelie LawDebbie (voice) | Debbie (voice) |
| TTeddy SkeltonNicky (voice) | Nicky (voice) |
| TTacy KnealeMog (voice) | Mog (voice) |