Apple Bloom yawned loudly and creaked her tired back. Still early. Too early for her. Crestopher hadn't even given his usual wake-up call -

Urrrrk-a-doodle-dooooo!

Ah, there it was. Still an hour until Applejack would get her up for school. She groaned, remembering that they had a history test scheduled for today, and she was pretty sure that she was going to fail it. She'd tried vainly to cram her head with facts about the Ancient Kingdoms, but it seemed to her like the longer ago something was, the harder it was to remember. The fact that the Ancient Kingdoms were constantly bickering with each other didn't help either; it was near impossible to distinguish one tribal skirmish from the next, which she was sure was fine and dandy for ponies of thousands of years ago, but a distinct lack of help to a schoolfilly who just wanted something she could easily memorise.

She made to rub her head with her hoof. CLONK!

"Owwww!"

Her eyes widened as stars began to pop and burst in her vision, her temple throbbing painfully. She'd somehow managed to hit herself in the face quite hard with her clumsy, flailing hoof. She screwed up her eyes and rubbed her head gently, before sitting up in bed.

Blonde manehair cascaded around her shoulders as she suddenly lurched backward with a yelp, her bed's headboard turning out to be too small to support her back. Her leg jerked reflexively and kicked off the blankets, leaving her braced awkwardly against the wall and staring at her large, orange body. A trio of red apples emblazoned both her flanks.

That's impossible.

She knew exactly what she was looking at, and yet... it wasn't possible. At all. Or if it was possible, it didn't make one lick of sense.

Ah've... turned into mah sister?

She pulled at her mane, tugging bundles of silky straw-coloured hair in front of her eyes in disbelief. Did Ah wish for this or somethin'? Ah mean, Ah know Ah was wishin' for mah cutie mark, but this isn't quite what I wus expectin'.

She rolled out of bed and onto her hooves, which clomped loudly against the floorboards. And this isn't mah room, either, she noted, looking at the stetson hat hung up on the door. This is Applejack's. So if Ah'm here... does that mean...

She pushed open the door and gently trotted across the landing to her own bedroom, nervous as she nudged it open. The room was still in the shadow of its curtains, but she could see a mound sprawled underneath the blankets, red hair poking out one end, a gently twitching yellow hoof from the other.

Ah don't believe it! That's me! But it can't be... Ah'm me.

She had a pretty good idea of who she was about to wake up, but she trotted in anyway and sidled along her bed, a strange tingle in her fur from the surreal scene she was now faced with. For the first time ever, she could see her own, gently snoring face, slack-cheeked and sputtering with each deep breath. It was strangely hypnotising, and not entirely flattering.

For a moment she wondered what the most polite way to wake herself up was. How does AJ do it? Normally by opening the curtains and yelling in mah ear... well, Ah'm not gonna be so uncouth to mahself.

She gently clutched the little yellow filly's shoulders and gave her a shake. "Hey, uh, me. Wake up."

"Mrrrf... wha? AB?" murmured the filly, her eyes fluttering a little before lidding once more.

"You need ta wake up!"

"Go back t'bed AB, 's too early." she mumbled.

That's mah sis all right, thought Apple Bloom. We musta swapped bodies! Oh sweet Celestia, she ain't gonna be happy when she finds out.

She trotted to the end of the bed and gripped the blanket in her mouth. Might as well get it over with.

Applejack jerked to alertness as the covers were whipped off her bed, exposing her to the cool morning air. She rounded on her sister angrily. "Whut in tarnation d'you think yer playing at... at..."

Apple Bloom gave a sheepish toss of her head as her sister got a full view of... herself. Her own body standing clear as sunshine not three feet in front of her. The filly began mouthing silently, too astonished to voice her words.

"Yeah, that was kinda mah reaction too," giggled Apple Bloom.

Applejack's eyes were wide in panic as she began feeling her face and body with her hooves, rolling over in the bed until she was clutching her raspberry-coloured tail. "Yer kiddin' me."

"Nuh-uh! It totally happened!" said Apple Bloom gleefully, stomping her heavy hoof on the floor.

"What... what did you do?" Applejack asked in despair.

"Ah didn't do anythin'! Ah woke up jus' now like this! Isn't it great?" She gave her hips a wiggle. "Ah finally got mah cutie mark!" she added jokingly.

"That's mah cutie mark and those are mah hoofs yer stompin' around in! You give 'em back!" demanded the filly.

Ah don't sound that whiny, do Ah? Ah really thought she'd take it better than this. Don't all adults secretly wish to be a foal again?

"Ah can't! Ah don't even know how this happened!" protested Apple Bloom. "Please, sis, let me play around with it fer a while! We swapped so it's fair, right?"

"There ain't no way Ah'm lettin' you out of this house with mah body," said Applejack flatly, clambering over the bed to look her sister in the eye, trying to ignore how incredibly weird it was to see her own green eyes gazing back mournfully at her. "The las' thing Ah need is for you an' them Crusaders to go gallivantin' around with it. Now if anypony knows how to fix this, it's gonna be Twilight, so you just -"

Apple Bloom gave her a soft push in the chest. She toppled back onto her rump.

Applejack gaped at her sister in surprise. Apple Bloom was looking wide-eyed at her forehoof, then at her, as if both were extremely complicated math problems.

A cold sweat suddenly flushed over Applejack's yellow coat. Oh no. Please don't be thinkin' whut Ah think yer thinkin'.

Her panic mounted for several tense moments of inaction, until she couldn't take it any more. Her limbs stiffened as she jerked into action.

"BIG MAC!" she squealed, spinning into a retreat, only to find an enormous orange hoof stuffed into her mouth as she was suddenly lifted off her front hooves, a powerful foreleg wrapped around her belly. "Mmmmf! No! Nuuuu!"

Apple Bloom was surprised at how easy it was to restrain a filly even when it was kicking and screaming. "Now calm down, sis! Yer gonna hurt yourself!"

"Mmrrrrf!" she coughed, manoeuvring her muzzle around the hoof. "Don't you dare, y'hear me? You are gonna be in so much troub- mmmrrf!"

"One day," said Apple Bloom gently. "Jus' one. That's all Ah want."

"I'll ground yer for one year-"

"Whut's all the ruckus?" drawled Big Macintosh from the doorway, a bemused expression on his face at the pair's antics.

"Mac, do something!" demanded Applejack, pulling herself from Apple Bloom's grip and toppling onto the mattress face first. "Yer sister's gone an' stolen mah body, an' now she's plannin' some kind of escapade!"

Big Mac stared at the filly, giving her a dull look. "That all?"

"What the - wha'd'yer mean, 'that all'? Don'tcha understand, yer big galoot?"

"What Ah think Apple Bloom is tryin' ter say," said Apple Bloom, giving the filly's mane an affectionate rub, "is that she don't wanna go to school today on account of her super-difficult history test that she ain't prepared for."

Applejack gasped. "Oh, don't you dare! Big Mac, it's me! Ah'm Applejack! Don't you listen to her!"

"Stop horsin' around, AB, yer gonna wake up Granny," said Big Mac sternly.

"Yeah!" said Apple Bloom, smirking widely. "Now you be a good girl an' get yer things ready fer school. An' don't forget it's Show 'n' Tell this afternoon, so, uh, find somethin' interestin' to talk about."

Huh. Ah didn't know Ah could could blow steam out o' mah nostrils like that. Maaaaybe Ah should skedaddle before somepony explodes.

"So... Ah'm just gonna go, uh, kick some trees, 'kay?" said Apple Bloom, trotting backward slowly from the fuming filly.

"Git back here!" Applejack raged.

"Apple Bloom! You behave yerself now." scolded Big Mac. "I got this, AJ."

Apple Bloom tried not to let out the whoop of laughter that was building inside her, as she left her brother to it. Halfway down the stairs, a torrent of high-pitched abuse exploded from her room with such force that she nearly tripped the remaining steps.

Huh. Wonder what some of those words mean.

She pulled open the front door, and began galloping faster than she'd ever run in her life. "Yeeeeeeeeeee-haaaaaw!"