Hermione Granger had left work early for the first time in her adult life. She should have used this once in a lifetime opportunity to go to sleep – it would have been her first full night in over a year – but instead she had followed a strange man to his flat. A strange man she had known for months, but a strange man nonetheless.

Oh what her mother would say! Actually, she knew exactly what her mother would say: she would say "I hope you at least had some fun, and didn't spend the whole night staring blankly at a pair of ribbons, wondering if you should rub them or not, trying to formulate rational hypotheses in the face of pure absurdity. Also, I hope you didn't antagonise your beau for his telekinetic abilities.". Evidently – also for the first time in her adult life – Hermione Granger would have disappointed her mother.

The tone of her letter was a bit more alarmed than Harry's. Syntactically, they seemed to respond to the same logic, though, which tended to indicate that they had the same meaning. As to what that meaning actually was, she felt like she was grasping at straws. The ribbon bit was particularly strange.

A significant portion of the night had also been allocated to explaining to Harry what she had meant before, about his telekinesis. She was still a bit flabbergasted that she'd been right about the whole thing: when he juggled, he didn't actually respect the equations of physics. During their flights, the balls should describe parabolas, whose sizes and widths would depend on the initial speed vector his hand defined for each throw. The trajectories could maybe be a wee bit skewed if the balls spun really fast, thanks to the Magnus effect. Instead they were all over the place. It still more or less looked like 'throwing and catching' in the abstract sense that they rose up, stopped for a bit, and came down in a pretty regular fashion, nobody – well, nobody normal – would notice the difference.

But Hermione had a habit of estimating these kinds of calculations in her head. When she watched sports – admittedly rarely – she would estimate the inner pressure and elasticity of the ball as it deformed against a football player's shoe... Generally up to the second decimal: she could do more, but measuring with her eyes wasn't that precise anyway. Her ears were much better. When she heard music – thanks to her perfect pitch – she could approximate the diophantine equations that enabled harmony to arise from each note to the next; she could marvel at the miracle of the twelve-tone-equal-temperament system mirroring the actual physical harmonics of each sound, and at the infinity of expressions that arose from the slight imprecisions in that mathematical mirror... At the same time, she mentally explored the hypnotic arithmetics of rhythm, and if the recording was especially good she could even discern the possible shapes of the drums from their sound – they were usually round, but sometimes she had a surprise... These exercises were actually so soothing she often couldn't fall asleep without listening to some light jazz.

If you have any inkling as to the sheer complexity of all that, then you can easily imagine that, every evening, as she bought her dinner from some mad juggler, finding the initial velocity of a ball and approximating the gravity field on Earth shouldn't be easy: it should be immediate. It shouldn't change for each throw, nor should it yield undefined results. And every evening, when it did, she wanted to protest... But she didn't have proof. So she just said "Hello, Harry" and just like that, physics snapped back into place and the balls fell like they should. She was kind of glad that she had now spoken and proven her claim to Harry: she had felt like a detective having caught a criminal red handed, as he transgressed the laws of physics.

On the whole, it had been a pretty long evening. In the end, she had slept a few winks: he had offered to share the only bed in the room – as chastely as he knew how, of course – as soon it had become too late for her to walk safely in his neighbourhood (which was pretty early). The bed was roomy enough, and she'd fallen asleep pretty much instantly, Chet Baker's rendition of My Funny Valentine firmly planted in her ears. But it was now seven and she had to phone in, to tell her students that she wouldn't be there today – that was yet another first for her – because they were going to pluck up their courage and rub the ribbons... She couldn't find his phone. She couldn't find him either.

She stood there for a bit, in the shirt he had lent her for the night, wondering wobbly-legged what to do. The flat was... frugal. Serpentine cracks adorned the walls and ceiling. By the way, the ceiling seemed to be vibrating. Not strongly, mind you, but silently. Too silently.

He was on the roof. He was doing something weird on the roof, something big. She jumped in her skirt, almost fell, and climbed upstairs more cautiously. By the time she got there, he had finished whatever he had been doing. She found him sitting crosslegged, panting slightly, while a light breeze lifted some dust off the ground.

She waited a bit: she didn't really want to intrude on whatever that was, but that thermos looked inviting. She felt a bit dehydrated... She borrowed it silently and took a few sips waiting for him to be done with whatever mental exercise he was attempting. Eventually he opened his eyes and stared at her, then at the thermos in her hand.

"There's pot in that tea"

She stared at it a moment "... Noted. Do you have a phone?"

"There's a payphone downstairs, I'll take you in a moment."

She sighed and let her back rest against the outer wall of the staircase. He stared at her from the centre of the roof.

"Come here a minute."

"Why?"

"You're stressed out, let me try to help you relax."

She sat in front of him. For the next few minutes, he had her close her eyes, relax her back and neck, breathe in and out in different rhythms. Then he tried to get her to block out all the noise, to have her consciousness move around in her own body, to visit each muscle from the inside, then seep outside into the air around her. He told her to 'look for the air currents'. To her surprise, she seemed to get it. Maybe it was an illusion, but it seemed that she sensed the wind around her, rather that on the surface of her skin... It was... theoretically possible. A kind of holographic correspondence, maybe: grasping the full knowledge of the volume from the information located on its surface... She felt the currents circling her, their intensity rising then subsiding, then rising again as though the void itself was breathing. She naturally synchronised her own rhythms with it, and tried to mentally feel around for what was happening further away from her body: the currents were moving around an obstacle, some distance in front of her; it had to be Harry. She tried to determine his shape in the negative space of her new perceptions. He... It looked like he moved a bit, in complete silence. He was... waving at her? So he knew she could see him? Was all of that just the tea? She tentatively waved back...

"Good." He said. He hadn't talked in a while... "Now let your worries seep away into the wind, progressively."

Well that didn't really mean anything. But somehow, a valve had already been opened. She felt a big, dark, pulsating tension leave her mind and flow into the air... It was slow at first, but she couldn't really stop it from accelerating... It felt so good, finally letting go of that chaos inside her...

One must still have chaos in oneself, she remembered, to be able to give birth to a dancing star. What a beautiful quote... but this... This seemed too literal to be what the moustachioed poet-philosopher meant. When she imagined a dancing star, the air felt warm around her...

Hermione tried to direct the tension away from Harry's silhouette... Around him maybe. It seemed like he was doing the same as her, kind of. As it left her mind, the dark chaos became bright: the same thing that had encumbered her mind with a somber weight translated outside of her into something messy and beautiful like a turbulent flow... It warmed the air some more... the currents rose up in a high-vorticity waltz around their bodies, and into the infinite space above. It felt happy and wonderful, like a hyperactive child captivated by a symphony for the first time. And Hermione was just smiling in peaceful silence.

There was a crackle in the distance, and the tiny voice of a woman – it sounded like it was trying to shout something... I understand that this must feel really nice, it said, but could you please stop what you're doing? Hermione didn't really want to stop. She wasn't even sure she knew how anymore. Or... Maybe... Maybe just open your eyes? That, perhaps she could muster.

It was harder than she expected, though. Her consciousness was spread thin and finding her eyes wasn't what one would call easy. She eventually found the muscles responsible for her eyelids' movements, and tentatively activated them. Her... other senses felt so powerful, it took a second for the sight to register. Harry hadn't opened his eyes, and the dancing star she had birthed... Well there seemed to be a column of bright golden flames encircling them. It was a pillar of fire, shooting up toward the sky, undulating slowly as it rose to tear up the heavy clouds... Oh. Oh god! Why was it so silent then?

With that thought, she allowed for the sense of hearing back around her: it came crashing like a nuclear blast, but before she could even reach to protect her ears, the sound was muffled again. Just like that. A flicker of thunder. She felt preternaturally calm, even though her brain was screaming that there was really no reason to feel so relaxed while engulfed in what literally was a cyclone made of fire, rising from her feet, slashing at the heavens above in roaring waves of dancing brightness. But at least if she didn't panic, then she could think. She stood up and approached Harry who apparently hadn't heard the tiny voice's polite requests or the nuclear thunder.

"Harry" She said, laying a hand on his shoulder "Now it's my turn to tell you what to do."

He didn't move, but the flames crawling outwards on the floor from under him changed from a happy gold to an interrogative orange. She couldn't help but notice that they were small and well behaved, when compared with the wild torrents of excited blazes that were still rushing outwards from under her.

"You need to calm the currents down. I'm sure you know how... Make them disperse, slowly... calmly..."

He began working at it. The winds slowed down, the flames cooled down... He seemed surprised at how much... vibrance there actually was around him. "Yeah..." She began, looking around her with her hand over her eyes "I may have gone overboard." He smiled a bit. When the maelstrom had calmed down, but not completely disappeared, she said "Now continue what you're doing, take a deep breath and slowly open your eyes."

Like her, the full consciousness of what was happening around him didn't strike at once. His brow furrowed as the fiery whirlwind became more and more red as it cooled down. By the time he seemed ready to speak, it had almost completely disappeared and Hermione could see silhouettes behind the thin, red hot, stormy veil of what had previously been her existential dread.

"Was that...? What we were doing? But I've done this a thousand ti– who the hell are these people?"

There were about twenty men and one woman around them, all dressed in preposterous fashions. They were pointing small sticks at them, and they seemed pretty cross... Almost ready to fight. One of them opened his mouth and was clearly about to shout something menacing, but the woman of the group – the only one who wasn't pointing a stick in their direction – shot him a furious glare and his mouth snapped shut, with an expression like a grown man who'd just been scolded.

"Hello" The woman said "Mr. Evans, Dr. Granger. If I'd known you were acquainted with each other I would have offered to meet you both directly. My name is Minerva McGonagall, I trust you've received my letters?"

They stood silent. Eventually Hermione spoke up "Uh... Yeah?". Minerva looked at one of the men around them: "Would you kindly go obliviate anyone who looks like they've seen that? If there's too many, we'll fabricate something about freak weather due to global warming or something." The men hesitated, to her annoyance "Please go. I'm perfectly capable of having a polite conversation with these two young people on my own." Eventually, everyone's image twisted around itself in a loud crack and disappeared, leaving only the three of them standing around, and around 66.7% of them utterly dumbfounded.

"So." She said. "Shall we go get dressed and have a cup of tea?" Their clothes evidently hadn't tolerated the flames as well as they had. Using a bit of ingenuity, though, the remains could be arranged to cover what needed to be. Barely.

When Hermione fumbled about trying to cover one particularly ill placed blackened hole in her garments – and as if what had happened hadn't been enough for one day – the still pretty turmoiled heavens decided to take their revenge against her. So they struck down upon her with a righteous bolt of lightning: there was a bright light accompanied by a loud crack, a scorching pain, and then nothing.