Will hadn't slept a wink.
He had spent the night trying to simplify the structure of the Bone-Growing Charm, bit by bit. It was anything but easy.
Adjusting its structure took immense effort and required magic. Will had already spent too much energy and magic converting the charm, and he was in poor shape tonight.
By morning, Will hadn't simplified it as he'd hoped. He had expected as much; this wasn't something he could finish overnight. Still, he estimated he could simplify the Bone-Growing Charm within the next few weeks.
After a sleepless night and a heavy drain on his magic, an exhausted Will collapsed onto his soft bed and fell fast asleep.
Will had thought that, with the Philosopher's Stone affair over, he could spend the rest of the term at Hogwarts in peace, researching whatever interested him.
But Snape soon dragged him off to brew potions.
Will noticed that Snape was in a good mood. He couldn't tell whether it was because Harry was safe for now or because Quirrell, that unpredictable threat, had been driven away.
He found out a few days later. Snape appeared in Defence Against the Dark Arts class, wearing a rare trace of a smile on his habitually cold face.
He had become the acting Defence Against the Dark Arts professor, while Dumbledore occasionally filled in for Potions Class.
Why only occasionally? Because Snape spent every available moment teaching. If two classes didn't overlap, he taught both. That kept him so busy that he casually tossed Will a few Potions books and told him to study on his own.
And once Harry was out of danger, Snape handed Will the job of brewing a substantial portion of the potions Harry needed to drink.
The other students were delighted with the arrangement. Aside