After learning that her friends, as well as herself, are the magical Elements of Harmony, studious unicorn Twilight Sparkle is sent by her mentor, Princess Celestia, to Ponyville to study the magic of friendship with help from her friends.
When Celestia and Luna decide to retire and hand off the ruling of Equestria to Twilight and her friends, it sends Twilight into a tailspin of self-doubt.
As Twilight and the rest of the Mane Six struggle to come to terms with the destruction of the Tree and Elements of Harmony, King Sombra sets his sights on conquering all of Equestria.
The Young Six respond to a magical summons from the Tree of Harmony, only to learn it has been destroyed, and it is up to them to figure out how best to memorialize it.
Twilight and Shining Armor pit their wits against each other to settle a long-standing sibling rivalry score - but they soon discover they're not the only competitors.
Twilight realizes she never returned a book to the Canterlot Library, and besides incurring the disgrace of a super-overdue book and huge fees, she may have caused her favorite librarian to lose her job.
Rainbow Dash's old pal Quibble Pants needs his friend's help to bond with the daughter of his new special somepony because, like Dash, she's a real sports pony. Unfortunately Quibble... isn't.
When Sandbar asks Yona to a "pony dance," Yona becomes convinced she must ponify herself to be a good friend, so she goes to Rarity and her friends for a makeover in appearance and personality.
Molder returns to the Dragonlands with Spike and Fluttershy to help cheer up her sensitive brother, but when they arrive, they are surprised to discover another problem - the dragon eggs aren't hatching.