Starswirl was looking right at Celestia.
“Do you understand?”
Rather than reply, she pulls a face at him, stretching her muzzle wide and flapping her tongue, letting her pink filly-mane flop over her face.
But her mentor doesn’t react.
“Mine ears discern thy plain instructions,” her little sister responds, sullenly, from behind, the smaller filly dwarfed by the adult-sized desk.
They were in ‘Advanced Potions’ — both siblings' least favourite subject/mentor combination. Luna had been kept back for extra practice, while Celestia had recently graduated. Her attendance today was unauthorised.
With a last face at Starswirl, Celestia prances softly to Luna’s desk.
‘What’cha writin’, sis?’
Celestia pouts her muzzle into Luna’s and waves her hooves. Luna’s brow remains furrowed and her tongue sticks out as her quill scribbles.
The filly ruler-to-be continues, ‘Pay back time, Moonbutt.’
Luna’s previous prank, using invisible ink, had just cost her a deadline and a perfect record in Equestrian Literature. It was only the latest loss in a long history of sibling prank-rivalry.
She turns back towards the chalkboard and waits for her moment to pounce, eyeing the white-crusted brows of their cantankerous mentor.
“As I was saying, Cetea Swirl is an ingredient of...” The lecture resumes.
At the end of his spiel, Celestia spies her chance when Starswirl turns to wipe the board.
Her horn lights up and she delicately teases the recently replaced chalk from the counter, trying to edge it along the lectern without either seeing.
With a delighted smirk, she succeeds in dragging it off, catching it in her magic. Holding it in place, she rises and shuffles quietly to the front of the classroom.
Her heart is in her mouth as he stops, and his ears seem to flick in her direction but, after a moment, he resumes wiping.
From her new vantage point she rolls the chalk across the floor, so that it rests on the wall below the board, now out of sight.
“Do you think—”
“Cogito, ergo sum. I think, therefore I am.”
Celestia groans internally as Starswirl interrupts Luna with his favourite joke.
As her sister proceeds with her question, she springs into action, using it as a distraction.
Celestia sticks her tongue out with concentration, slowly raising the chalk up behind them. Using his body to block Luna’s eyeline, she writes slowly to muffle the noise. She expertly imitates his flamboyant cursive:
‘Cogito, ergo butt.’
Satisfied, she lets the chalk fall to the floor, where it shatters noisily.
“Luna!”
Celestia has to swallow a delighted giggle as she sees the horrified expression on his face.
“Explain yourself!”
She stands next to Starswirl, looking down at her sister and frowning like a teacher, imitating the other’s censorious gestures.
Luna’s eyes dart to the board — there is a tell-tale scrunchiness as she tries not to laugh.
“’Twas not I!” she manages, between gasps.
Her lecturer’s face is stern. “Aside from its asinine message, it lacks noun-verb agreement.”
Celestia sticks her tongue out at him, and returns to the board to scuff out the rest of the words with her hoof, so it only says:
‘go butt’
Luna guffaws and stuffs her hoof into her mouth.
Celestia retreats as he wipes it away.
Rubbing her hooves with glee, she returns to Luna’s side.
In her saddlebag, she has a love-letter from Luna, from before her mark — a Hearts and Hooves card to her teacher:
Dear Teach
Please hold my heart
In your hoof
And be my speshul somepony,
<3 Woona x x x
She had found the note abandoned among her sister’s things on a prank-hunt weeks before. She waits for the perfect moment to use it — when Starswirl collects Luna’s work.
As he strides back to the lectern, with a quick flick of her horn, she performs the swap.
Celestia leans over her-filly fetlocks eagerly.
To her delight, the stern teacher’s expression twists, the corners of his mouth twitching.
'Go on!' Celestia encourages.
She sees Starswirl suck his teeth.
But ultimately she is disappointed, as he masters himself.
“Princess, please kindly approach.”
Her sister’s eyes go wide and her cheeks redden as she slides her chair out and approaches the lectern.
With a squeak of dismay, Luna sees the note. Celestia sees her go into her tantrum routine: ears flat, back arched, light blue tail swishing.
“Aaah!” she screeches. “Mine most foul sister must have—“
To Celestia’s amazement, however, she sees Starswirl lean forward to hold her sister’s hoof. As he does so, his horn lights up.
“Is it true?”
Luna only stutters.
“Luna?”
Celestia sees her sister turn briefly, eyes wide, before meeting Starswirl’s gaze and nodding.
“We shall formalise the state of affairs later.”
‘What!?’ Celestia rears back, almost toppling her chair as she does so.
The two pay her no mind.
He hands Luna back the letter. “See that it does not fall into the wrong hooves.”
Narrowing her eyes and pointing a hoof, she declares, ‘Your turn, Bossy Beard!’
Looking for a way to make mischief, she circles behind him. It was funny eyeing the stallion from this angle as he droned on. She was over-familiar with his mannerisms: the beard-stroking and wizard hat bell-fiddling. She sees he also sways back and forth, swishing his silver tail, occasionally reaching down to tease its strands.
Bored, she muses a while, eyeing the clasp on his robe, considering options.
“No, no, no!” he suddenly shouts, sharply.
Celestia instinctually recoils.
“How many times must I tell you? You must mix the harmonium gently! Gently!” He hunches his shoulders and sighs. “Here, let me demonstrate.”
Luna was wearing her frustrated face, lips pouted, muzzle scrunched — mid-experiment.
‘Tsk, tsk, sister.’ Celestia shakes her head. ‘You are making teacher cross.’
She trots up behind Starswirl, enjoying reaping the reward for her earlier efforts — she had previously interfered with the pre-prepared ingredients that Luna was using.
“All wrong, as I thought.”
“Thou…!” Luna’s eyes flash and she stomps her hoof. A lightning bolt sounds outside — storms were not infrequent during Potions.
“Already your elder’s inferior in magic, you wish to follow suit in temper?”
‘Ouch!’ Celestia winces.
Luna just grinds royal teeth.
“Allow me.”
Starswirl discards Luna’s mucky brown mixture and begins afresh, using her ingredients to mix.
Celestia beams, anticipating her teacher’s embarrassment when the botched materials spoil his demonstration. But her joy is short-lived.
“The problem, tyro, is your inept distilling. These are impure and therefore useless.” He gestures to the ingredients, dismissively. “I see we will have to return to the fundamentals. For now...”
Starswirl levitates ingredients over from the lectern and Luna’s already red cheeks deepen into an angry purple.
'OK, maybe I went a little far…'
But, as she sees him begin to mix, an idea occurs.
While he busies himself with the potion, she rifles through her saddlebag for one of her favourite ingredients — something she always carries: an incendiary called infernium.
“Observe. Now you mix the harmonium like so,” he was saying, dryly.
Celestia sidles up to him.
‘And regard,’ she imitates, ‘as I burn off my silly beard.’ Reaching around his hoof, she adds the dash of infernium, and it immediately reacts.
WHOOOSH!
Both Luna and Starswirl jump back.
“Merlin’s Mane!”
He frantically pats his beard, upsetting the mixture on the table as he does so, some of which spills onto his cloak.
Celestia grins triumphantly.
‘And now my work here is done!’ she thinks, and turns to leave.
But she freezes when she hears a familiar voice in her head. ‘I think, Your Royal Highness and soon-to-be Ruler of Equestria, that your work is just beginning.’
Her eyes dart to Starswirl, who has stopped patting his beard, and is now looking at her, coldly.
“Greetings, my sister,” Luna says, out loud.
“You can’t see me!” Celestia holds up her, still transparent, hooves.
“I am afraid that is where you are mistaken.”
Luna nods, the corner of her mouth twitching.
“What are the limits of a potion of absolute invisibility? You graduated this class many moons ago, so you should know.”
Celestia racks her brain, flummoxed.
“Perhaps your graduation was premature. Educate her, Your Highness.”
In a smug tone, Luna recites, “’While to ordinary pony senses thou art undetectable, a simple spell of magical sight will reveal the active enchantment on the user. A significant flaw, if the target is magically gifted’: paragraph four, page eighty-nine of the Advanced Manual.”
Celestia gulps. “When?”
“You must have used magic,” Luna observes.
‘When I caught the chalk!’ she curses.
“The error of a novice. It was then a simple matter to telepathically instruct your royal sister to play along.”
“At Drama, I am thy superior,” Luna adds, in the same tone.
“Admittedly, I had thought better of you than to indulge in a room filled with explosive substances.”
Celestia’s cheeks prickle, and she looks down.
“What do we say?”
“I’m sorry,” she mumbles.
“Properly, Your Highness.”
“I am sorry, Professor ‘The Bearded’.”
“Good. Now, after you clean up this mess,” he says, gesturing to the workbench and his cloak, “we will resume the lesson, and since, as you have so vividly demonstrated, you lack the advanced understanding expected of a graduate of this class, we shall have to schedule further lessons — examined, of course.”
Celestia’s head, already low, droops to the floor, letting her pink mane spill over.
Luna grins.
“Please, anything but that... I’ll never prank again; I’ll give you a castle when I inherit, I’ll—”
Starswirl shakes his head and, flicking his beard with his hoof, abruptly turns and stalks to the lectern, his spoiled cloak flying.
Luna shakes hers in a similar fashion, “Oh, my fickle and unworthy sister.”
Celestia glares at her and once their mentor is out of earshot, hisses, “Stupid Woonabutt.”
“Firebug.”
“Bat-filly.”
“Sheep-brain.”
“Lunatic.”
“Pest-ia.”
“SILENCE!” Starswirl thunders. “DO I MAKE MYSELF CLEAR?”
