The Postmare Always Gets Her Due
"Now that we've invented paper," Princess Celestia tried to explain to her sister Luna, "We can send a message to another pony without the necessity to write the message on a THIRD pony, let alone ordering that third pony, upon pain of death, to seek out the recipient and display their flank."
This is how the Equestrian Postal System USED to work. Really! 😛
A dull dun color, the pegasus mare was easy to miss if you weren't looking for her. But in her line of work, being inconspicuous was an advantage.
Sometimes she avoided hostile flying creatures by traveling on foot, threading her way through rough country where she could hide among the trees and scrub.
Even when she flew, she often sheltered among clouds, especially the dark gray clouds that herald storms.
But now, well over three hundred miles from her journey's beginning, she sighted her destination. She grinned, letting herself glide downwards.
Perhaps a quarter hour later (she wasn't sure, because clocks hadn't been invented yet), she landed atop a castle's highest tower.
Her eyes scanned the flat, slaty surface beneath her, finding a rectangle of wood and iron. With one hoof, she stomped upon that rectangle...once, twice, three times.
That done, she stepped back and away from the rectangle.
A moment later, the hatch popped open, erupting in a shower of arrows.
The mare dodged, and dodged again.
"Duchess Abacus Cinch!" the mare shouted. "I have a very important message for you...POSTAGE DUE!"
"No!" answered a voice from beneath the roof. "Impossible! Nopony knows my current address! Any mail sent to me is...undeliverable!"
The dun mare peered towards the hatchway with one eye, while her other eye swiveled to keep watch behind her. (She didn't LITERALLY have eyes in the back of her head, but she had the next best thing.) As a black-clad assassin's dagger thrust towards the mare's back, the delivery mare stepped sideways, and kicked.
Unprepared for the counterattack by a pony who he'd THOUGHT was looking away from him, the assassin lost his balance, falling off the tower.
"AAAAAAAA!" he screamed. "I think I landed wrong and sprained my ankle!"
"Duchess!" the delivery mare shouted. "Come up here and accept your official letter from the Diarchy, or...I shall be forced to levy additional forwarding charges!"
"Never!" the duchess declaimed. "A small army of henchponies blocks the way between you and myself. Try as you might, you shall never succeed."
"Neither snow, nor rain, nor heat, nor gloom of night--" the dun delivery mare started to reply...but a large, muscular pony flipped up onto the tower's roof from below. He pressed a strong hoof over the dun mare's mouth, and his other foreleg wrapped around her neck.
The dun mare elbowed her attacker, who only squeezed harder. The delivery pony threw herself down on her side, which slammed her attacker against the tower's roof. Despite himself, he grunted softly.
That, though, was barely the battle's beginning.
***
"So you see," the dun mare explained, "skillfully wrapping packages is an important part of my job."
Lying on the ground in front of the delivery pony, a crimson alicorn struggled against the many loops of twine that restrained her body. "This is an affront to my dignity! A commoner like you deserves to die, for DARING to even touch me!"
The delivery mare giggled. "Didn't you see my flank?" She looked at herself. "Oh, sorry. OTHER flank."
The mare rotated a hundred and eighty degrees. Upon her flank (the OTHER flank), somepony had written a note in long lasting ink, signed with a hastily scrawled signature and a simple yet artful sketch of a crescent moon.
"See?" the dun mare giggled again. "A letter written and signed by Princess Luna herself, ordering you to cease your rebellion and return to Canterlot."
"You think you've won," the duchess sneered. "You think you've delivered your message. But there's something you don't know. A secret that ruins your plan."
"What's that?" the dun mare asked, her eyes big with innocent curiosity.
The noble pony laughed, with a loud, echoing evil. "I can't read!"
The dun mare sighed. "I suppose there's nothing to be done for it."
"YES!" the noble cackled. "I WIN!"
The delivery mare grasped one end of the twine between her teeth, and flapped her wings. Delivery mare and duchess rose into the sky.
"NOOOO!" the duchess wailed. "I'm afraid of heights!"
"GGGSTRA DLLLVRRY CHRRGES MMMR EPPLLL," the dun mare said.
***
Two weeks later in Canterlot, the dun mare dropped the rebellious noble through a pony sized mail slot, into the Equestrian Postal Service's "Special Delivery" office, Canterlot branch.
The duchess landed on a tabletop, where along with other 'handle with special care' packages, she was inspected, stamped with three different rubber stamps, sorted, and finally tossed into a special high security mailbox. On the box's front, a sign warned
For Princess Luna Only
After three days, Luna checked her mail, collected the disobedient duchess, and gave her a stern talking to.
***
"So you see," Princess Celestia finished, "Princess Luna is VERY enthusiastic about the Equestrian Postal Service. She's a big fan. She simply...hasn't kept up with the latest innovations. And by 'latest,' I mean the last thousand years or so."
Derpy giggled. "So that explains it! I wondered why the princess was trying to write on my flank."
"Yes," Celestia said, "It's all perfectly logical."
Luna looked embarrassed. "I do have one thing I want to say to you...Miss..."
"Derpy!" the postmare said. "Derpy Doo, Postmare Second Class."
Luna stood up extra tall and straight. She raised one foreleg, which snapped into a salute against her forehead. "Thank you for your service, Postmare Second Class Derpy Doo."
Derpy grinned. "No problem, princess!" She returned the salute. "One thing, though..."
"What is it?" Luna asked.
"Do you have anything I can use to get all this ink out of my coat? Maybe a special shampoo?"
***
"I find that...a bit hard to believe," Twilight Sparkle said.
"But it's the truth!" Derpy insisted. "I didn't WANT everypony's mail to arrive two hours late. It was all the princesses' fault."
Twilight Sparkle sighed. "It's fine. Don't worry about it."