It's Franklin's birthday! Luna and all the villagers are planning a surprise party, and Franklin's family are visiting from the moon.
While the party is being set up, Luna takes Franklin book shopping.
They find a padlocked book of fairy tales, which the bookseller tells them is full of dangerous magic.
Luna's tortoise, Neil, can't help picking the lock... but when he peers inside, the book swallows him whole.
Franklin and Luna dive into the book to rescue Neil.
They tumble into cobwebbed forests and meet dusty fairy-tale characters who have been trapped inside these pages for hundreds of years.
After several encounters and some narrow escapes, they finally find Neil - who has won a gold medal after racing a hare - and, all together, they break out of the book and into the real world.
Exhausted but victorious, all the fairy-tale characters, Franklin, Luna and Neil arrive at Franklin's birthday party.
They're not sure it's a happily ever after, but they're certainly very full of cake... and that will more than do for now.