His wand felt unconscionably heavy in his sleeve. It was as though the metaphorical weight of the coming battle was literalizing itself in his weapon. Kevin's mind drifted to his parents, still largely in the dark at home in Manchester, probably wondering how Kevin's exams figured to be going. No, after all that had happened this year, he had to go home in a train car, not a box.
He fixed Su with a strange look, striking an odd balance between apprehension and envy. Without breaking his gaze, Kevin slid his wand into his hand. It felt foreign somehow, as though his hand had fixed itself to the stick he held for a couple months.
Kevin closed his eyes, summoned the strongest happy thought he could, and stretched his wand over the banister.
"Expecto patronum!"
Nothing happened.
Frustrated but completely unsurprised, Kevin exhaled slowly and looked back at Su. His expression read of resignation, not anticipation.