On the eve of the anniversary of Twilight's arrival in Ponyville, the Princesses vanish mysteriously, and the girls are sent to investigate. What they discover shocks them.
The Corruption that turned Luna into Nightmare Moon, Princess Invidia, has returned, and this time she isn't alone. She has gathered almost all of the other villains from the show, Gilda, The Diamond Dogs, Flim and Flam, Queen Chrysalis and a severely weakened King Sombra, as well as an army of Shadowbolts, Windigoes, and Changelings to destroy the Elements of Harmony and take over Equestria. The Mane Six prepare to fight the new forces of evil and save the day once and for all.
Beware spoilers. Not that this will be published soon.
- Action Girl: The Mane Six, duh.
- Crazy Awesome: Pinkie Pie, of course.
- Five-Man Band: Princess Invidia's group:
- The Cameo: Prince Blueblood makes one, guarding the gates to Canterlot Castle under the promise that Princess Invidia would give him a position as the captain of the royal guards.
- Evil vs. Evil: Discussed; Twilight decides that "in order to beat a villain, you have to think like a villain". For this reason, she enlists the help of the newly reformed Trixie and Discord.
- Smug Snake: Princess Invidia.
- Yank the Dog's Chain: King Sombra, in a Danny Phantom Shout-Out.King Sombra: I LIVE!Princess Invidia: To serve me.
- Creepy Twins: Flim and Flam to a degree.
- Disney Death: The Mane Six besides Spike and Twilight:
- Applejack and Applebloom are sent hurdling off the edge of a cliff...which happens to be adjacent to Appleoosa.
- Pinkie Pie distracts and is apparently devoured by a swarm of parasprites...her sisters and her parents show up and drive them off before this can happen.
- Rarity apparently drowns in a river...but is rescued by Steven Magnet.
- Fluttershy is apparently eaten by the Everfree forest's evil trees...but was rescued by the mantcicore.
- Rainbow Dash gets sucked into a hurricane...and gets spit back out in Cloudsdale where she enlists the help of the Wonderbolts.
- Living Lie Detector: Applejack after Princess Celestia gave her a special magical implant that amplifies her Element of Honesty to make her immune to any form of deception.
- Deadpan Snarker: Twilight, Spike and Rainbow Dash
- The Quisling: Prince Blueblood.
- Pony Puppets: Zecora suffers this thanks to King Sombra's magic.
- Evil Twin: Applewither, an evil clone of Applebloom created by King Sombra.
- Unusual Ammo: Pinkie uses her party cannon to tie up Gilda and the Diamond Dogs in streamers at one point.
- Taken for Granite: What the villains do to the Princesses.
- Even Evil Has Standards: It's telling that Discord shudders at the mere mention of King Sombra's name.
- Eldritch Abomination: Invidia starts out as this.
- Equine Abomination: When she gains a body.
- Torture Technician: King Sombra.
- Master of Illusion: King Sombra. Also, there are several forests that create illusions that the girls has to go through.
- The Woobie: Fluttershy and Spike when they're captured by the villains.
- Mama Bear: Twilight shows doubts about her quest. When Spike gets kidnapped, however, she immediately decides to lead the Mane Six into battle.
- Apologetic Attacker: Zecora while under Sombra's control.
- Tagalong Kid / Little Stowaway: Applebloom.