This story ignores Season 6 and splits from the universe from "The Cutie-Remark".

During the last bits of the Cutie Re-mark, a new portal opens unexpectedly, dragging Twilight and Spike into another timeline. Without the spell, they are stuck in a timeline with the smell of war everywhere, a place where the magic of friendship is no more. To return to her timeline, she has to fix this timeline and end this ten year war against Starlight's regime.

But Twilight will realize that sometimes, she has to get her hooves dirty and commit horrible crimes to better the whole world and save her friends.

"Twilight, get your gun, get your gun, get your gun.
Take it on the run, on the run, on the run.
Hear them calling you and me,
Every Mares of Liberty.
Hurry right away, no delay, go today.
Make Celestia glad to have had such a lad.
Tell your sweetheart not to pine,
To be proud her mare's in line."

Parodied from "Over There"

Based on WW1.

Note: Tags will probably change as the story progresses. Chapters will be updated periodically.
Special Thanks to MisterNick for his help.

Several years had passed after Tirek's defeat and everypony is preparing for this year's Summer Sun Celebration. But Twilight is not feeling well. Several nightmares are haunting her, she has got bad headaches and a really mad mood. Although Spike and the others tell her to go and fetch help, she refuses. But when some dark incidents and curses happen, Twilight realices too late, they had walked into a trap and it has snapped behind them. For the foe is inside of her and preparing her last and final strike. To turn the celebration into a true nightmare.

Twilight Sparkle, Celestia and Luna are transported into a strange alternate Equestria, the Land of Always Summer, where the day lasts forever and a terrible queen rules with an iron hoof.

Feel free to check out or add to the story's TV Tropes page.

A long lost tome found again by Twilight Sparkle.
An upcoming event that drives Celestia's advisers insane.
Strange sounds from the Everfree forest which poor Fluttershy just can't handle on her own.

When Celestia calls a meeting between all princesses, it's clear something big is going on.

A dark cloud hangs over a small town in the middle of nowhere, a haunted mansion casting a further shadow over the listless inhabitants' lives.

It sounds like the most unlikely place to find a scared filly like Scootaloo, but this is where the Element Bearers have to fight for the Cutiemark Crusader's life, and their own.

During the course of a sleepover at Ponyville Castle, it is revealed that neither Twilight nor any of her friends have ever kissed a stallion. Things quickly get competitive, and soon Spike, the only male within striking distance, is forced to run for his life.

EDIT: WOW! Already featured only a few hours after publishing 6/20/17! Thank you all!

One fine morning, Spike woke up early and ran some errands. Then he found Discord putting up a seller's stand, apparently ready to open his own business. One which offers a one-day transformation into anything the user wants. And he apparently had the patience to set up his shop LEGALLY. Twilight and the others brace themselves for the inevitable...

(Content of future chapters controlled by user votes!) (Now with Tropes!)

Now with a 'dramatic' reading: Prologue

Current poll: The transformation is chosen already (Tatzlpony!) You pick who becomes the Tatzlpony! (Voting ends 6/25 at 5PM EST)
Previous poll: The Cutie Mark Crusaders (63 votes out of 390) and Age Manipulation (83 votes out of 392) won
Previous poll: Sunset Shimmer (transformation error won with 83 votes out of 325)
Previous poll: Princess Celestia (85 votes out of 397) and Seapony/Siren (104 votes out of 421) won
Previous poll: Trixie (86 votes out of 357) and Alicorn (90 votes out of 338) won
Previous poll: Fancy Pants and Fleur Dis Lee (genderswap won with 199 votes out of 381)
Previous poll: Princess Luna (zebra won with 85 votes out of 368)
Previous poll: Rainbow Dash (griffon won with 274 votes out of 596!!!)
Previous poll: Rarity (diamond dog won with 184 votes out of 444!!!)
Previous poll: Starlight Glimmer (changeling royal (Chrysalis-type) won with 74 votes out of 257)
Previous poll: Pinkie Pie (alicorn won with 80 votes out 282)
Previous poll: Spike (unicorn won with 60 votes out of 225)
Previous poll: Applejack (minotaur won with 56 votes out of 254)
Previous poll: Fluttershy (draconequus won with 75 votes out of 181)

(Voting closes after a week from the posting of the current chapter)

A machine made for war awakes in a new world. Stuck in surroundings which puzzle it; can it, or will it be able to become something more than what it is?

Crossover with Keith Laumers Bolo-verse
Other tags include : Slice of Life, Possible Romance believe it or not! And a bit of humor.
Please beware of any spoilers in comments as well

Some things in this world happen by chance. Others do not. Twilight Sparkle is about to learn a disturbing truth that will turn her world upside down.

- Originally written May 2011 for Deviant Art

Reading this story first is strongly recommended:
(Blood is Thicker) http://ciroton.deviantart.com/gallery/26378692#/d3e1ndq

Credits:
~Image by JohnJoseco~ ~Edited by BrotherPrickle on Deviant Art~