So apparently there's a place "where rainbows are made" that was once considered little more than a pegasus bedtime story, but turns out to be real when some malfunction causes rainbows everywhere to suddenly get pulled away into a single massive cloud in the sky. Once again, the Crystal Brighthouse provides a convenient solution by teleporting the main six ponies up into the clouds (and allowing them all to walk on clouds) to find that rainbow making machine. Once they do, Zipp discovers a blockage within the machine and has to fly through a dangerous vortex to reach it, but only when she receives help from Pipp and Sunny is she able to reach the machine and remove the blockage, which turns out to be an unfortunate pegasnail. With the rainbow machine cleared and all rainbows restored everywhere, they return to the ground by riding on some of those rainbows.
I honestly don't know what to make of this episode. As far as I know, this is the closest we've ever seen G5 make any reference to how G4 pegasi could manipulate the weather, and it's with some kind of rainbow-producing machine in the clouds that seemingly no one has bothered to keep an eye on. A small part of me would like to see future episodes make additional suggestions on the pegasi possibly rediscovering their weather controlling abilities, but I realistically don't have high hopes for that. Overall, just a rather mediocre episode for me (unless if it leads to something better like I just mentioned).