A bald Christmas tree, a missing butler, and a runaway red bus ― this year, the royal Christmas is anything but ordinary.

When King Charles and Queen Camilla's festive plans spiral into chaos, they find themselves improvising decorations, shopping in disguise, and stumbling into more mischief than they bargained for. Meanwhile, beneath London, a lonely white mouse named Snowball escapes his neglectful owner and discovers a secret world of theatre mice rehearsing a magical pantomime at the spectacular London Palladium. But when Snowball is snatched away and the Underground's handmade presents vanish, it will take the daring Special Mouse Services, a touch of royal mayhem, and the magic of teamwork to save Christmas Day.

Brimming with humour, heart, and festive adventure, this enchanting tale, the fourth in the enchanting Underneath the Underground series, introduces readers to some new mousy characters along with many faithful favourites who have captured the imagination of children everywhere. This latest adventure proves that with friends, courage, and a little imagination, Christmas can be truly unforgettable.