In the kingdom of Galaxandria, Princess Celeste Starr is in BIG trouble. The King has to admit that his daughter has become far too spoiled and needs to learn a lesson. So he tells her she cannot be called Princess anymore as she is not behaving like one - AND she needs to mix with real people. She's sent to the Kingdom's old Post Office which is a place her mother loved before she disappeared some years ago. Celeste is told she has to sort out the towering piles of unsent letters and the infestation of stardust bunnies so that people can start getting their letters on time again. With her new assistant, Podge, she gets to work, ready to fight to get her Princess crown back and return to the palace. And it turns out she's good at it. All that Princessly bossing around and organising people is really paying off.

But she quickly discovers two things . One - people have started using magical wurm devices to communicate without having to lift a finger and so they don't seem bothered at all about getting actual letters again. And two - it turns out her mother didn't just love letters and the post office, she was connected to it in a much bigger way .