Only after feeding Sirius did Will return to Hogwarts.
He still needed to talk to Dumbledore that night. Dumbledore needed to know what Lucius and the others were up to, too. Will had built a good working relationship with him, and he didn't want any unexpected complications.
Before that, though, he needed dinner. He had returned a little late, and Hogwarts' dinner service was already over.
At the entrance to the Kitchens, Will ran into Harry, who had just eaten his fill.
"Will!" Harry greeted him. "Just got back from extra lessons?"
Everyone knew about Will's extra lessons by now.
"Oh, Harry. Where are you off to?"
"I'm going to see Lupin." Harry glanced around. "I want him to teach me a spell. Remember the one he used on the train? The one that drove off the Dementor?"
"You mean Expecto Patronum."
"Yeah. I think we really need it. Otherwise, we can't even go back to the High Tower." Harry waved. "I'd better go find Lupin. Talk later."
"See you."
Will intended to ask Lupin to teach him the Patronus Charm too, though he wanted it for something else entirely.
The Hogwarts Headmaster's Office.
Will laid everything out. "That's the whole story. It was arranged when they invited me last Summer Holiday; now we're discussing the details."
"I see..." Dumbledore adjusted his crescent-shaped Glasses. "You've handled this well, Will. In fact, I think this could be very good for you. Since you have the ability, you ought to show the Wizarding World what you can do.
"It may also lull the Death Eaters into a false sense of security. Still, I don't think it's enough."
"Not enough?" Will hadn't expected Dumbledore to say that. Given Will's age, Potion Transfiguration was already a substantial piece of research.
"No. A Sleeping Charm