Loss
Tom saw out of the corner of his eye as she disappeared mid-thought.
He turned his head so fast, he thought his neck might have strained. But there was only empty grass where she had sat moments before. He shot to his feet, wand in hand, and cast a spell he should have cast when he'd first arrived here- he might have found her earlier: Homonioum revalio. He cast it as widely as he could, feeling his magic stretching out from him like a circular ripple in a still dark pool. He waited as the ripple spread and spread, but it was as he'd suspected. She was gone.
Suddenly the splendor of the stars seemed cold. And the dim light became threatening. He felt a twinge in his chest, and was irritated when he realized he felt forlorn.
He didn't know how to cast himself back, and the thought was like ice over the warmth he'd been feeling after the duel and the delight in magic. He wondered why she had been pulled back before him. He wondered how long he would be stranded there. He cast a Tempus charm, followed by a series of wards that'd alert him if anything tried to sneak up on him. Then he put his back against the tree and slid to the ground to wait, rest and replenish his magic.
There was nothing to fear he reminded himself- he was magic, he trusted magic, he trusted himself. He would survive, as he always did, no matter what.
He only had to wait 3 minutes and 49 seconds.
Between one blink and the next, he found himself in his dormitory. He threw his forearm over his eyes to shut out the brightness of the cheery yellow lamps that illuminated the dungeon. As his eyes adjusted, he realized his dorm-mates were sitting in a circle, playing exploding snap, exactly as before.
He felt relief, overwhelming relief- like water down a parched throat- to be back in the familiarity of Hogwarts. He quickly shrugged it off. Of course he was back, he had known he would be alright.
Already, the plane and the girl felt like a dream, like he'd just fallen asleep over his book and dreamt up a strange girl with wild warm magic. But when he cast Priori incantatem, all the spells he had used over the course of the evening had really been cast.
And if that wasn't enough proof, he noticed a black feather was stuck to his sweater. He placed the feather carefully in his diary.
He was awake- long after his dorm mates had finished their game, turned the lamps out and fallen asleep- thinking about unfamiliar stars, a curly haired girl and her resilient swifts.