An old woman, Doddery, gains Equestria magic that lets her drain the age out of others, restoring her to her youth. She turns Rarity into an old woman right before an important fashion show she is competing in, and later turns Flash into a little kid and Trixie into an adult. Now everyone needs to stop her and turn everyone back into their normal ages.
Tropes:
- Age-Gap Romance: This is lampshaded between Flash and Adagio, since Adagio is technically Really 700 Years Old. Flash is turned into a little kid by Doddery, with Adagio commenting she didn't think she was dating someone that young, and later when Adagio is turned into an old woman too and they see each other in their changed states Adagio comments that their age difference is finally showing.
- Batman Gambit: Trixie talks down about Volt-Edge to the eight-year old Flash, saying how lame he is and how he could never beat Doddery. This irritates Flash enough that he transforms into him to prove her wrong. This not only stops Flash from recklessly transforming into Way Big like he planned to, but his childish temper at Trixie's taunting causes his electric powers to explode and zap Doddery.
- Chekhov's Gun: Shining says he was planning to test out a new teleporter system at the base today before Twilight complained about him trying to do fun stuff without her. He later uses the teleporter to get himself, Flash, and Trixie back to the fashion show when they realize Doddery is attacking it.
- Fountain of Youth: Doddery's watch is infected with Equestrian magic, allowing it to drain the age from something and then transfer it to something else. Doddery uses it to restore her own youth, then goes around town absorbing the age of several other elders and then transferring it to various kids, robbing them of their youth.
- The Mind Is a Plaything of the Body: After being reduced to an eight-year old kid, Flash slowly starts acting childish. He ends up being distracted by a cartoon instead of chasing Doddery, asks for ice cream with Puppy-Dog Eyes, and stubbornly declares how he intends to go Way Big against Doddery.
- Misplaced Retribution: Doddery recognizes Rarity from the contest and identifies her as one of the "brats" that made fun of her before stealing her youth, even though Rarity was one of the only ones who didn't make fun of Doddery and actually considered checking to see if she was okay.
- Not Hyperbole: Flash claims that Rarity could make a great dress in her sleep, before claiming that isn't a boast, Applejack once had a sleepover with her and woke up to find Rarity sleepwalking while taking her measurements.
- Post Tantrum Sleep: After the eight-year old Flash as No-Edge has an explosive electric temper tantrum, he becomes tired and says he is going to take a nap before collapsing and instantly falling asleep in the middle of the battle. He wakes up as soon as he is changed back to his normal age.
- Teens Are Monsters: Downplayed, but the other teens competing in the contest besides Rarity are very rude to the elderly, mocking Doddery and later Rarity after she is aged up.
- Who Wants to Live Forever?: The Dazzlings realized that after they lost their immortality when they were stripped of their magic they now have a better appreciation for life, now remembering events they went through much more fondly as opposed to before how they just blurred together when the three did nothing but cause arguments to feed on the resulting negativity.
- You Have GOT to Be Kidding Me!: Flash lets out an annoyed "Seriously!?" when he realizes he is now a little kid again and his clothes are now way too big for him to wear.
