[WARNING: S5E3 episode synopsis spoilers!] The ponies try to make Princess Twilight's castle feel more like home after finding out she's been avoiding it.
On the Feast of Hearth's Warming Eve, Princess Celestia and Princess Luna risk their lives in a blinding snowstorm to bring essentials to a pair of poor ponies living in Canterlot
Princess Celestia saves a pony from Rainbow Falls from stoning by her fellow townsfolk and gives her sanctuary in Canterlot. While investigating the matter further, she discovers of laws made without her approval.
Humans don't have (as much) magic as ponies, so they get their psychedelic kicks in... other ways. Fluttershy's friend Tree Hugger has procured a substantial amount of one such way of getting one's kicks. Twilight's about to blast off.
In this sequel to "Defender of Equestria," a Changeling General goes on trial in Canterlot for numerous war crimes, including kidnapping Cadence and Twilight, while Shining Armor's mentor and predecessor attempts to make amends with Celestia and Luna