Princess Celestia and Princess Luna decide to retire and hand off the ruling of Equestria to Twilight Sparkle and her friends, which sends Twilight into a tailspin of self-doubt. Meanwhile, an ancient villain bands together a legion of nefarious characters to conquer all of Equestria, challenging Twilight Sparkle and the rest of the Mane 6 to step in and save the day.

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.

Twilight and Shining Armor pit their wits against each other to settle a long-standing sibling rivalry, but they soon discover they are not the only competitors.

Twilight realizes she never returned a book to the Canterlot Library and may have caused her favorite librarian to lose her job.

Rainbow Dash's old pal Quibble Pants needs help to bond with the daughter of his new special friend because, like Dash, she's a real sports pony.

When Sandbar asks Yona to a pony dance, she goes to Rarity and her friends for a makeover in appearance and personality.

Grogar sends his legion of doom on a mission to become allies, but his plan works too well and they almost become friends.

Smolder returns to the Dragonlands with Spike and Fluttershy to help cheer up her sensitive brother, but when they arrive they discover the dragon eggs aren't hatching.

Apple Bloom's obsession with catching a magical creature causes Applejack's plan for a harvest to go awry.

Starlight Glimmer relishes her role as school counselor and encourages the students to come to her anytime about anything, but she becomes overwhelmed and learns a lesson.

Unexpected visitors to Ponyville threaten to break up the Cutie Mark Crusaders forever.

Luna and Celestia take a sister vacation while Twilight and her friends struggle to cover the princesses' many royal duties.

When Pinkie Pie needs to find her life's purpose, she seeks out her old friend Cheese Sandwich, however she soon discovers that the unimaginable has happened.

The School of Friendship is starting a buckball team, and Rainbow Dash has to come to terms with the fact that she won't be coaching the team.

Twilight's hopes of keeping her Trivia Trot winning streak alive are waylaid when she's unexpectedly paired up with Pinkie Pie, who has never been to a trivia night before.

Twilight is determined to make Celestia and Luna's last Summer Sun Celebration memorable, but things start going horribly wrong.

When Fluttershy and Angel Bunny's relationship hits the skids, Zecora gives them a potion to help them understand each other.

Rarity slowly starts to grow jealous when Spike starts to spend more time with Gabby rather then her.

When Starlight is told that she will run the School of Friendship after Twilight becomes the ruler of Equestria, she must choose a Vice Mare, putting her friendship with Trixie to the test.

When a previously unheard-of author writes a novel trashing Daring Do, exposing her as a real pony, and praising Dr. Caballeron, Rainbow Dash rushes to defend her friend, while Fluttershy is more sympathetic to the "misunderstood" Caballeron.

When the Cutie Mark Crusaders are magically transformed into grown ups, they discover that growing up the right way means gaining experience and wisdom that simply can't be rushed.

When Big Mac and Sugar Belle decide to propose to each other, everything their friends do to help ends up making a mess of the whole thing.

A villainous alliance unleashes their power on Equestria.

Twilight Sparkle and friends tell a story about how Twilight had to make a difficult decision when Celestia and Luna retire and hand the throne to Twilight who must choose to either be the rightful ruler of Equestria or stay in Ponyville with her friends.