Magical Mystery Cure

Magical Mystery Cure is an episode of the third season of My Little Pony Friendship is Magic. It aired as the thirteenth and final episode of the third season, and the sixty-fifth episode overall. The title of the episode alludes to Magical Mystery Tour by the Beatles. The episode features a total of seven songs, the most songs in a single episode thus far, beating out the previous record of four set by A Friend in Deed.

Production and development
M.A. Larson wrote the episode in November 2011. Show storyboard artist Sabrina Alberghetti helped with some clean up on the episode, and said in late December 2012 that she used "what little power" she has to throw in one of her favorite background ponies, who she specified is not hers.

In the summer, musician Andrew Stein played mandolin for show musician William Anderson on a short cue for an episode of the third season,   and Stein wrote in early November 2012 that "Apparently it's in the season finale this year" and that it "almost didn't happen" as it was "extremely lucky" that their schedules coincided for it; however, Anderson ended up not having any role in the episode at all, as Daniel Ingram and Steffan Andrews received the only music credit. Stein later confirmed that his mandolin part was cut along with Anderson's work when the music production shifted entirely to Ingram and Andrews. In early August 2012, Anderson wrote that "thirteen already exists" and quoted a subsequent response "You could also interpret him as saying that 313 has already been completed, probably ahead of some of the others, but since I'm just some random nobody, I'd have no idea why they would do that" with his own response "You don't?"

On February 9, 2013, the episode was shown early at an official Hub event in Los Angeles. On February 15, 2013, Meghan McCarthy announced on her Twitter page that the season three finale will have continuity into season four as it will be separated into three parts, with season three's finale being served as the first part of a three-part story.

Morning in Ponyville
Twilight Sparkle awakens to a bright and sunny Ponyville day, singing that she's certain today is going to be perfect. During her song, she wakes up Spike (who goes right back to sleep) and passes by numerous ponies around town. As her song reaches its climax, Twilight is suddenly interrupted by a splash of rainwater. She immediately accuses Rainbow Dash for the rain but instead finds Rarity on a nearby bridge attempting to manipulate the rainclouds. And to Twilight's shock, Rarity has Rainbow Dash's cutie mark!

The Cutie Mark Switch!
Twilight questions Rarity about why (or even how) she's controlling the weather and what happened to her cutie mark. Rarity doesn't know what Twilight is talking about. She explains that she is simply doing what she's done since the day her cutie mark first appeared. Rarity's "quilt" of clouds causes it to rain and snow simultaneously in Ponyville, earning her the irritation of the town's residents.

Twilight and a very sleepy Spike go to Fluttershy's cottage (which, according to Rarity, is actually Rainbow Dash's cottage) to find out what's going on. They find a sullen Rainbow Dash inside and open the cottage door to the sight of dozens of woodland animals running amok. What's more, Rainbow Dash has Fluttershy's cutie mark. Twilight finds Fluttershy at Sugarcube Corner with Pinkie Pie's cutie mark, trying to make ponies laugh. Pinkie Pie, wearing Applejack's mark, is trying her best to manage Sweet Apple Acres, and Applejack (with Rarity's mark) is at Carousel Boutique trying to make dresses. Each of Twilight's friends fail miserably at their new tasks and are clearly unhappy, but sing that they are just doing what their cutie mark is telling them to do, that it's their destiny to do so.

Star Swirl's unfinished spell
Twilight and Spike frantically return to the library as Twilight realizes what must have happened: The night before, Princess Celestia had sent her Star Swirl the Bearded's spell book (seen at the end of The Crystal Empire - Part 2). The last page in the book contains Star Swirl's secret, unfinished masterpiece, and Celestia had tasked Twilight with making sense of the spell, believing she is the only pony capable of doing so. She had started by reading the spell aloud:

"From one to another, another to one. A mark of one's destiny singled out alone, fulfilled."

- Star Swirl the Bearded's unfinished spell

As she did so, she inadvertently cast the spell on the nearby Elements of Harmony, causing them all (aside from Twilight's) to change colors. Twilight deduces that this caused her friends' cutie marks to be swapped around as well. Spike suggests casting a counter spell, but there is none. He then suggests her memory-fixing spell from when Discord was freed the first time. Twilight explains that it isn't her friends' memories that have been altered, but their true selves. And Zecora's cure for the cutie pox wouldn't help either. Realizing their dead-end situation, Spike reasons that maybe their friends will grow to like their new lives, but Twilight truly doubts it.

Twilight goes up to her room and laments over her terrible mistake and how much misery she's brought to both her friends and to Ponyville. Spike consoles her, saying he's sure she'll find a way to help her friends and fix everything. Reassured, Twilight looks at a photograph of her with her friends.

"They mean more to me than anything. ...My friends."

- Twilight Sparkle

Suddenly, Twilight starts to glow, and she gets an idea: if she can't remind her friends of who they are, she'll remind them of what they mean to each other. She puts the Element of Magic on and places the rest of the Elements in their chest, then heads out with Spike.

Finding their true selves
Twilight and Spike find Fluttershy in front of a hot-air balloon. Disappointed by her failure to make anypony laugh, she's decided to move back to Cloudsdale. Before she does, Twilight asks her if she could help Rainbow Dash with the animals. Fluttershy is very unsure, but is willing to do whatever she can to help her true friend.

Back at the cottage, the situation is even worse than before: Rainbow Dash is tied up in a pot, with the animals dancing around her. Fluttershy asks Twilight for a spell, but Twilight refuses and tells her to handle the animals. Fluttershy steps in to feed the woodland creatures, and they instantly calm down and warm up to her. She begins to glow, realizing that this is what she's meant to do, that this is her destiny. Twilight then places the Element of Kindness on Fluttershy. In a burst of comprehension, Fluttershy finally remembers who she is, and her cutie mark returns to normal.

One by one, Twilight restores the memories and identities of each of her friends by reintroducing them to their correct roles, with the help of her restored friends and the Elements of Harmony: Rainbow Dash helps Rarity clear the weather, Rarity helps Applejack make dresses, Applejack helps Pinkie Pie save Sweet Apple Acres, and Pinkie brings smiles back to everyone in Ponyville.

Finishing the spell
With her friends restored to their true selves, Twilight has another epiphany: She knows how to complete Star Swirl's spell! She and her friends return to the library, and Twilight rewrites the spell's incantation:

"From all of us together, together we are friends. With the marks of our destinies made one, there is magic without end."

- Twilight's revision of Star Swirl the Bearded's spell

Having completed the spell, the Elements of Harmony spark to life, bathing Twilight in their light. She suddenly vanishes into thin air, leaving a scorch mark on the wood floor in the shape and pattern of her cutie mark.

Twilight's transformation
Twilight appears in a strange space full of stars and nebulae. Princess Celestia appears before her, congratulating her on creating a brand new form of magic, accomplishing something even Star Swirl the Bearded couldn't, since he didn't understand friendship the way Twilight does. She leads her student down a pathway of stars as dozens of images float by, depicting key moments in Twilight's life and study of magic and friendship. Celestia sings of how proud she is of her student, and that she is now ready to fulfill her destiny.

Suddenly, a shifting blob of magenta energy emerges from Twilight's chest and begins to swirl around her while a pulsing white light grows from her very center. Twilight is lifted into the air, the whirls of magenta and white blanket her, and she disappears in a brilliant flash, like the supernova of a star.

In the night sky over Ponyville, Twilight's cutie mark appears, now sporting six small white stars instead of its original five) and floats down to the ground. Twilight's friends watch as the light fades away and Twilight appears... with a pair of feathered wings!

As the others gather around to marvel at Twilight's new look, it becomes clear that not only has she gained wings, but has also become physically taller too: about half-a-head taller then the average mare, much like Princess Luna and Princess Cadance. Rarity states that Twilight has become an alicorn, with Fluttershy commenting that she looks just like a princess. Princess Celestia appears and states that Twilight is a princess, explaining that since arriving in Ponyville, she's displayed the charity, compassion, devotion, integrity, optimism, and leadership that a true princess is known for. Twilight worries that this means she won't be Celestia's student anymore. Princess Celestia says she'll still be there to help and guide her, but Twilight has just as much to teach now as she has to learn. Twilight's friends and Celestia then bow to her.

The newest princess in Equestria
The next day, a princess coronation ceremony is held in Canterlot, which Princesses Celestia, Luna, and Cadance preside over. Celestia addresses the assembly of ponies, saying Twilight has proven without a doubt that she is prepared to be crowned Equestria's newest princess.

"Fillies and gentlecolts, may I present for the very first time... Princess Twilight Sparkle!"

- Princess Celestia

The audience beholds Twilight as she and her royal procession enter the throne room. Before the three other Princesses, she is crowned with a tiara modeled after the Element of Magic. On the castle balcony, Twilight waves to a crowd of hundreds of cheering ponies. Princess Celestia prompts her to say a few words.

In her first official address as princess, Twilight says friendship was at one time something she didn't care much about, but she wouldn't be standing there if it weren't for the friendships she's made. She expresses to her friends her undying gratitude, and considers herself the luckiest pony in Equestria. It's an emotional day for all, even Shining Armor, who Twilight is surprised to find crying. Twilight's friends congratulate her, and she meets the five of them in a group hug.

In a reprise of the episode's first song, the newly crowned Princess Twilight Sparkle is brought out of the castle in her own chariot before she jumps out to trot and sing alongside her friends. Ponies line the city streets to witness the coronation parade, including Derpy, Cloudchaser, and Flitter. In a final shot of Canterlot, Twilight takes flight on her new wings and soars at the screen, proclaiming everything's going to be just fine.

Quotes

 * Twilight Sparkle: And I know for absolute certain, that everything is certainly fine!


 * Applejack: Twilight...? Is that you?
 * Rest of main cast: [gasps]
 * Applejack: What... I've never seen anything like it!
 * Rainbow Dash: Ha! Twilight's got wings! Awesome, a new flying buddy!
 * Rarity: Why, you've become an alicorn. I didn't even know that was possible!
 * Pinkie Pie: Alicorn party! [blows kazoo]
 * [crowd cheering]
 * Fluttershy: Wow... you look just like a princess!
 * Princess Celestia: That's because she is a princess.
 * Main Cast: Huh?
 * Pinkie Pie: Hold on a second! [drinks] [does a spit-take]


 * Twilight Sparkle: A little while ago, my teacher and mentor Princess Celestia sent me to live in Ponyville. She sent me to study friendship, which is something I didn't really care much about. But now, on a day like today, I can honestly say I wouldn't be standing here if it weren't for the friendships I've made with all of you. Each one of you taught me something about friendship, and for that, I will always be grateful. Today, I consider myself the luckiest pony in Equestria. Thank you, friends. Thank you, everypony!


 * Shining Armor: Twilight! I'm so proud of you!
 * Twilight Sparkle: Are you crying?
 * Shining Armor: Of course not, it's liquid pride. Totally different thing.