The sound of someone coming through the window wasn't an owl. Al turned to Dad and his smile widened. It was hard to keep it off his face all day, since Severus saw him off to work with their usual coffee-flavoured kiss-and-Apparate-out routine.
"I've read these ones already, back in school," Al said. "They just needed some attention, and proper arrangement." He moved the stack parallel to the edge of the desk and made sure it remained perfectly so, thus completing his routine. "I do that to Severus' books but he doesn't let me near the caged ones."
He didn't ask which Uncle, even though there were several alternatives, merely nodded.
"I've determined the source of your happiness the other day," he declared, pleased with himself for solving the puzzle.