This story happened 2 years after Rarity's marriage with Applejack. The two lived a happy life, although Applejack had drinking problems. It was still tolerable for Rarity though.
But one night, Applejack had too much.
"Darling, it is 3 a.m. in the morning!" Rarity accused.
Dead drunk, Applejack stumbled into the house.
"Honey, I've told you MANY times, it's OK if you're off drinking with friends, but call me if you're going to be back late!" Rarity said, angrily.
She walked up to Applejack and tried to keep her balanced.
"Did you know how worried I wa-"
Before Rarity could finish, Applejack swiftly pushed her off. Rarity lost balance and hit a wall, then fell to the ground. Applejack lifted her front hooves and stomped hard on Rarity's head.
"I've had enough of your nagging all these years, you damnation! You ain't the boss of me!" Applejack shouted proudly.
She tried to walk to bed, but she tripped on Rarity's body and fell down.
Before she knew it, Applejack fell asleep.
The morning sun shined brightly in the living room.
Applejack got up from the floor.
She rubbed her eyes, but suddenly stopped because she didn't realize her hoof was wet.
AJ thought it was water at first, only to scream in terror when she realized her hoof, and a large part of her body was red after regained vision.
She looked to the side, and it was when she found the source of the blood did she realize she had totally messed up.
"Rarity? Wha...I...?" Applejack stood completely still, dumbfounded by the sight in front of her.
She walked towards Rarity's dead body, and noticed something below her head. AJ looked under it, and found a pair of scissors, with one of the blades piercing through the back of Rarity's head.
AJ instantly recalled stomping on something last night.
Remorse for her irresponsible actions, Applejack turned herself in. She was sentenced to life due to murder.
The day after the news were out, Fluttershy applied for a job as a prison doctor so she could be with her friend and made sure she was okay. Soon she got accepted.
Another two years passed.
Applejack was still remorseful for her actions. She deeply missed the old happy days she once had. Life in prison was incredibly dull and miserable, and she begun to hope she was freed. But that was impossible. The owner of the prison had a heart of stone. Any pony who were sentenced to life or executed was never seen again.
The only good thing about prison was that she got rid of her fond of alcohol, since no one gave her any to drink, but every time she thought about drinking, she would only feel worse, and mournfully cry, "Oh! If only I stopped drinking! Nothing would happen! If only I stopped! Rarity!"
Unable to overcome her kindness, Fluttershy came up with a plan to help Applejack escape. Applejack, whilst still regretful, accepted her offer, because she couldn't overcome her honesty, either.
"So, tomorrow night, I am assigned to dispose of a body. The guard who has your cell's key has a pet hamster, and the two don't get along that well. I asked it to steal the key and bring it to you tomorrow night, in exchange of freeing it, and it said yes. After you leave the cell, sneak into the morgue and hide into the coffin, which is used to store the corpse. Doctors will inter it tomorrow morning, and when they're gone, I'll come and dig you out. You can go live a new life afterwards!" Fluttershy cheerfully whispered her plan into Applejack's ear.
Applejack cried once more, thanking Fluttershy of her kindness.
"Oh, one thing though. You might need to spend a night with the corpse." Fluttershy addressed.
"It's fine. That's much more than all I'm asking!" Applejack responded.
"Do not look for another way out! There are guards EVERYWHERE at EVERY exit at night! I made sure no one else knew about this, so please do not worry." Fluttershy reassured, with a smile on her face.
Everything went according to plan, and Applejack successfully snuck into the coffin Fluttershy prepared for her, although she did not run into Fluttershy at all.
She was slightly creeped out by the thought of staying in a dark, creepy coffin with a dead body, but considering she would be free tomorrow, and since she didn't want Fluttershy to be in trouble, she overcame her fear. Besides, there was no decomposing smell, so the conditions were totally bearable.
After a few hours of waiting, Applejack finally felt like some pony was moving the coffin.
Then she felt like she was sinking through a surface.
"Hmm. I must be under the dirt now." Applejack said, slightly feeling queasy immediately afterwards.
The coffin stopped moving.
"Okay. Fluttershy should come soon enough." Applejack said, happily.
Applejack waited.
It felt like hours past.
Applejack could still see nothing but darkness.
"Fluttershy? Where are you?" Applejack said. She was getting very anxious, and the rotting smell that was gradually growing was not helping at all.
Suddenly, she felt her hoof touch something. It didn't feel like a part of the dead body. After examining the thing, she realized it was a flashlight.
Applejack didn't want to use it, because she really didn't want get any visual reasons to scare herself.
But still, no one came.
AJ's anxiety grew to terror. Desperately, she switched on the flashlight to look for things to help her out of the coffin.
Unintentionally, the light ray hit the corpse's flank.
"Wait. That cutie mark..." Applejack muttered. Sweat gushed out on her face rapidly.
Slowly, with her hooves shaking, she moved the flashlight's light beam.
Applejack saw the horrifying face of the dead pony.
Then she let out the most bone-chilling scream that could ever be made by ponies.
But no one on the surface could hear a thing through the thick coffin walls and the many layers of soil.
The corpse in the coffin was Fluttershy.
She had been killed by the owner for attempting to harbour a criminal by helping her escape.
It was at that moment Applejack realized, she was buried alive.
