My Little Pony Equestria Girls 2013

Plot
The newly crowned Princess Twilight Sparkle visits the Crystal Empire with her friends for a royal summit with Princess Celestia, Luna, and Cadance. That night, Twilight's crown and Element of Harmony is stolen by Sunset Shimmer, a bitter unicorn and former student of Celestia. After being chased through the castle, Sunset throws the crown into a magic mirror and follows after it. The princesses inform the ponies that the mirror leads to a different world, and task Twilight with retrieving her crown on the other side before the portal closes again for thirty moons, or else the Elements of Harmony borne by her friends will no longer protect Equestria. Despite Celestia's insistence that Twilight must travel alone, Twilight's dragon assistant Spike anxiously jumps in after her as she enters the mirror.

Twilight and Spike find themselves in a world inhabited by humans and are transformed into a teenage human girl and dog, respectively. While struggling to adjust to her new body and surroundings, Twilight investigates a nearby high school where she recognizes several of the faculty and students as ponies she knows in Equestria, including her friends Applejack, Fluttershy, Pinkie Pie, Rarity, and Rainbow Dash. She quickly befriends the five girls, helping to bridge the animosity that Sunset had created between them in the years prior to Twilight's arrival. Twilight discovers that Fluttershy has found the crown and given it to Celestia, the school principal, who mistakes it for a prop meant for the student who is elected Princess of the Fall Formal. Twilight decides to run for Fall Formal Princess against Sunset, who tries sabotaging Twilight's campaign first by uploading a humiliating online video of Twilight behaving like a pony, and later framing her for wrecking the formal decorations in the school gymnasium. However, Twilight's new friends, including Sunset's ex-boyfriend Flash Sentry, help counter these ploys and improve Twilight's popularity among the students.

At the formal, Twilight wins the election and the crown, but Sunset steals it after threatening to destroy the portal to Equestria. Upon donning the crown, Sunset transforms into a demonic creature and uses her newfound powers to brainwash much of the student body into becoming her army with which to invade Equestria. When Sunset tries to attack Twilight, her friends race to save her, evoking the crown's magic that protects them and temporarily gives them pony-like attributes. The magic of their friendship reverts Sunset to her human form and breaks her spell on the other students. Sunset becomes repentant, and Twilight asks her friends to become Sunset's new friends after she is gone. Twilight spends time celebrating with her friends at the formal before she and Spike take the crown through the portal, which closes behind them. Twilight and Spike return to Equestria, transforming back to their original forms on arrival and reuniting with their old friends.