Princess Celestia closed her bedroom door after thanking the guards on duty standing watch just outside. The glow around her horn flickered before vanishing. She let the tiredness of the day sink into her. Her regalia she removed by hoof instead of magic, the gold adornments left on the floor instead of placed properly where it was supposed to go. She reminded herself to pick it up in the morning before any of the castle staff saw the clutter. They got so worked up if the royal accoutrements weren't treated with the utmost respect.
Here in the privacy of her bedchambers, after the sun was put to rest, the day felt so much longer than it could possibly have been. All the diplomatic visits and official holiday appearances. Everypony, neigh, everybeing wanted to spend at least a moment in her presence on holiday. All believing the superstition that speaking to Princess Celestia on the winter holiday would bring blessings in the next summer. It had stopped being flattering several few centuries ago.
She had enjoyed the yearly Canterlot pageant more than usual this year. Her faithful student was so adorable as Clover the Clever and all six of her friends had done their parts wonderfully as well. As always, it amused her how the depiction of the six founders continued to drift over the centuries.
Now the day was over. Her sister could handle anything that came up. It was time for Celestia to enjoy the restful sleep of a long winter night, a luxury that added even more thankful thoughts about her sister's return.
*clank*
As the one in charge of the beginning and end of each day, Princess Celestia had a near perfect sense of time.
*clank*
So she knew that it had only been ten minutes between resting her head on her favorite comfy pillow and when she started hearing what sounded like the clank of chains above her.
*clank clank*
Her efforts to ignore it only prompted the sound to increase, almost sounding impatient. Princess Celestia sighed before opening her eyes to see what foolishness was going on. She was stunned into speechlessness by the eerie sight that greeted her.
A pale white figure wrapped in clanking chains floated above Celestia's bed. The pony-like apparition was a lifeless lack of color that no living pony's coat could match. The figure glowed with a dark aura of spectral light as she hovered. The ghost was that of an earth pony, so it could not be using magic or wings to float like that.
"I am the ghost of your last personal secretary," the totally spooky ghost spoke in a low voice. A low voice both obviously repeating lines from a script and just as obviously trying to apologize with its tone. "You will be visited tonight by three spirits to show you the errors of your selfish life."
"Hope you had a good Hearth's Warming Eve, Miss Sunshine. I trust you are enjoying your retirement?" Princess Celestia was confused, but that was no reason to be rude to a close friend.
"I'm keeping busy, your highness," the ghost replied automatically. Then her glowing aura shook her.
"Stick to your lines," whispered absolutely nopony perfectly concealed behind an invisibility spell.
The white ghost sighed and perfunctorily shook her forelegs to make her chains clank again. Each movement seemed to scatter ethereal dust from her mane, coat, and tail. To the casual observer it might possibly look like flour used to recolor a pony's appearance.
"I'm a warning to you that if you do not mend your selfish ways, you will end up a wandering ghost like me. Weighed down by chains of duty and regret."
Then the ghost floated backward, stopped, then turned in place as casually as possible before continuing. All with a tired look on her face.
"I'll see you next week for tea," Princess Celestia called out just before the very spooky ghost was covered in darkness and disappeared.
The sound of the bedroom door opening and closing in the deep darkness was just Princess Celestia's ears playing tricks on her. No doubt the stress of such a frightening experience had unnerved her. Very spooky ghosts do not need to use a door to leave, after all.