My Little Pony: Equestria Girls - Through The Mirror

Following Twilight's coronation, she travels with her friends to the Crystal Empire for a Royal Princess Summit. The entourage buzzes with excitement, but Twilight remains uneasy about the wings and the responsibilities they bring. The gathering promises hope but also questions about her new role as a princess.

A cloaked pony steals Twilight's crown during the summit, triggering a frantic chase through a shadowy castle corridor. The culprit is cornered but escapes through a mysterious mirror as the crown slips away. Twilight begins to realize the mirror could hold the key to reclaiming what was lost.

The next morning, Celestia explains that Sunset Shimmer escaped through the mirror. The mirror originated in Canterlot but has been moved to the Crystal Empire and is now under Cadence's care. The portal only opens once every 30 moons and with three days left, Twilight is tasked with stepping through to retrieve the crown.

Twilight and Spike step through the mirror and arrive in a new world. Spike becomes a dog, and Twilight awakens as a teenage human girl. She adjusts to her new appearance and heads toward a massive building she first mistakes for a castle.

In the new world, Twilight wanders the halls among a sea of teens and is helped by a blue haired boy. Fluttershy explains that the crown is intended for the Fall Formal in three days and hints Sunset has won the crown the last three years. Twilight realizes she must compete fairly to win.

To prove herself, Twilight announces she will run to be Princess of the Fall Formal. She meets Pinkie Pie, Rainbow Dash, Applejack, and other friends who offer encouragement and warnings. The social maze of the school becomes the backdrop for her plan to unite different groups.

Sunset Shimmer confronts Pinkie about planning chaos and hints that bringing an Element of Harmony could cause trouble. Twilight begins to sense the deeper trouble caused by Sunset's scheming. She retreats to study the school's social mechanics.

Twilight learns that to win the crown she must win over the entire student body, not just one group. The group hatches a plan to unite rival factions around school spirit by reviving an old idea, headbands with pony ears and tails. A key meeting with Pinkie Pie and friends sets the plan in motion.

That afternoon, Twilight and her friends lead a mass performance about helping Twilight win the crown, and a wave of camaraderie sweeps through the school. The rival cliques begin to thaw as students sing along and join in. Sunset's influence begins to waver as trust grows.

Vice-Principal Luna presents photos that seem to show Twilight at fault for gym damage, threatening her reputation. Flash Sentry arrives with new photos proving the earlier images were doctored, clearing Twilight's name. Despite the relief, the gym damage postpones the Fall Formal by a day, heightening the clock's pressure.

Facing the clock, Twilight weighs honesty against exposure but chooses truth with Spike and Pinkie Pie urging her on. The friends rally to repair the gym in time for the celebration, repairing the damage and restoring trust. The sense of unity spreads across the school as preparations resume.

The Fall Formal arrives and Twilight is crowned the winner. Sunset Shimmer refuses to accept defeat and uses a sledgehammer to seize the crown, threatening to merge powers from both worlds. Twilight's friends unleash their combined magic, breaking Sunset's hold and freeing the students from mind control.

After the celebration, Twilight returns to Equestria through the portal, bringing stories of her new friendships. She is greeted by a new member of the royal guard, Flash Sentry, hinting at a possible romance as her friends tease. The adventure closes with Twilight sovereign in her world and strengthened friendships bridging dimensions.