[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.
Canterlot Castle: a place of wonders and revelations, countless advances having been made within its sturdy walls. However, what should have been a great leap forward has instead flung a pony into the unknown...
[based of the Eternal Sunshine of A Spotless Mind] If you love someone, you let them go. Even if that means dealing with the pain of forgetting and being forgotten.
Discord and Princess Luna have fallen in love, that nopony else knows about. But suspision starts rolling across Equestria as a crazy night starts going on, and Celestia needs to find out what the heck is going on.