The year is 2147, and humanity is nearly extinct.

Presumably the only two humans left are living on the Founder - a spaceship meant for a much larger crew than two people. The ship was meant to find inhabitable planets to restart humanity on, although their mission obviously hasn't gone well.
The ship is floating above a planet filled to the brim with life. But the life is sentient, and the two humans don't want to drive the various species out of the planet - or, worse, possibly start a war.
The ship is old. Power is scarce without the use of solar panels, and the engine could fall apart at any second.
The two humans expect to die at any second.
They don't expect to be given another chance.

Rainbow Dash is flying through the skies around Ponyville when a strange, rectangular object falls out of the sky above her and bonks her on the head.
This is enough to cause concern, and she brings the object to Twilight so she can look at it. After the small meeting, the object is left with Twilight and Dash leaves to fly.
She should've been more careful.
(This story is on hiatus until I get better at writing the Mane Six in-character.)