This story is a sequel to CRISIS: A Royal Affair

A mysterious portal appears in the Everfree Forest one afternoon, and Twilight Sparkle and her friends are sent to investigate. The portal transports them to another Equestria, one full of evil and darkness, where they have to fight to survive on the long journey home. A pony named Tick Tock, a guardian of this new world from forces of chaotic magic, offers to find a way to take them home. They make other new friends along the way, but also new enemies, primarily six evil counterparts out for blood.

The central story of the CRISIS-verse. This story takes place during Season 3 of canon, before the Keep Calm and Flutter On episode.

Thanks to Devnator, BeeAre, and The Living Couch who assisted with editing and as creative consultants. Cover art by Starlight Spark.

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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.

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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

It is the year 2038, and the Earth is slowly being consumed by a space-borne monstrosity dubbed the Black Tide, which is using nanotechnology to remake the planet into something hideously alien.

Erin Olsen works for Project Harmonics, humanity's last-ditch effort to find a new world before the Tide can wipe them out. But when that world is found, and it turns out to be occupied, Erin will need to find the courage to face the unknown in order to save the inhabitants of both worlds.

(Many thanks to Easteu for the fantastic cover image for this story!)

Now with its own TV Tropes page

There is now a follow-up to this story: Sunflower - Side Projects
Sequel: Project Sunflower: Harmony