This isn't where I belong. I left all this behind years ago, moved on with my life. But a mare from my past brought me back, and now she won't let me go. So I'm stuck here, trying to make the best of it with ponies that don't understand me, don't even like me. But when something moves in the darkness, and when things go wrong in the cold, dead night, they'll turn to me to try to set things right.

Why? Because once a police pony, always a police pony.
~~
This is a spin-off story to 'Why am I Pinkie Pie?!', and will contain spoilers for that story, but it's not necessary to read that story to understand this one.
Cover art by the talented Conicer
Need more Cinnamon Swirl? Merlos the Mad wrote a fanfic of this story!

There is now a side-story: A Hard Day's Nightmare Night

This story is a sequel to XCOM: Ranger

With the fate of her friends on Earth hanging in the balance, Twilight has to hunt myths to figure out a way to cure Sunset and save Templar Laetitia.

Taking Daring Do as her guide—and accompanied by a ragtag team of griffons, a Skirmisher-turned-breezie, and Rainbow Dash—Twilight must travel across the lands at war with the Storm King, to reach Ancient Fleece, find a lost city, and obtain the legendary sword of King Disc Ovis: The Algae Photis.

Cover art created for this story by the talented: LateCustomer

Before you read: This is a side-story to XCOM: Ranger.

I will provide all possible information needed for those that do not have the time—or inclination—to read the other story to still be able understand this one. It's a LOT of info, however, and I'm not just going to dump it all in one go. The backstory will emerge as the story progresses.

Unhappy that her future as a member of the monarchy is denied by Celestia, Sunset Shimmer escapes through Starswirl's mirror into another world, planning to take it over to prove once and for all she was fit to rule. What she didn't expect—besides a species change—was to arrive in a world already conquered.

TvTropes Page (Just created! Needs Help!)

Art (Will contain spoilers)

Sunset Shimmer - Bloody Sunset

Spoilers Ch. 11+: Angel - Angel and Sunny
Spoilers Ch. 18+: Princess - Comic
Spoilers Ch. 121+: Alejandra Acevedo - Flying at the speed of death
Spoilers Ch. 161+: Apple Bloom - Bloom
Spoilers Ch. 180+: Food - Sunset's Party Dress
Spoilers Ch. 185+: Fugue - Fugue by Rametep
Spoilers Ch. 197+: Exhausted

(Art is always welcome!)

WARNING: CONTAINS SPOILERS FOR THE WHOLE STORY: TIMELINE

Young Cheerilee is happy to have finally settled down with her family in a nice town like Ponyville, and she's not about to let her nervousness about her first day of school stop her from making new friends. Most of her classmates seem nice, but...

There's one young colt who'll barely say two words to her. And she's determined to find out why.

SPOILERS IN THE COMMENTS!

The star system Omega Centauri was just another oddity on a map to scientists in the not too distant future. However when they found the star was orbiting an earth-sized, earth-like planet instead of a black hole as its motion had suggested, a mission was scrambled to investigate this most unusual of celestial behaviors.

Hamstrung by politics, and nearly crippled before it began, the 'Lone Ranger' mission was reduced to just one crew member and left to his own devices.

These are the logs of Arrow 18 and its lone commander. This information is classified TOP SECRET by the Global Space Agency.

Do NOT tell the princess.