With the Galactic Federation gone, Rick and Morty planned to make rainbows return to their neighborhood for some reasons. So they find planet 5E4960 and travel there.

And when they do travel there, they're now stuck for 2 weeks because Rick's portal gun won't work. They also have to put up with the ponies' shit.

edit: This got featured on the 'Popular Stories' list in 5/3/2017, just after it's release. :D