You lift up the top of the piano, and look inside, investigating the strings. You are looking for what is causing the piano to plunk, yes, very good, Gryffindor. Following the strings you find not a wand or stick, but a very specific article of clothing. Do you remember you wore it your first year? The item that sent you to Gryffindor! A house it does amend!

It’s the Sorting Hat. It’s the item you seek! You found it, congratulations! Now off you go to to find the next. You are almost done, at last.

Where to next, girl?

A rat squeaks as it crosses in front of you. Don't mind him. He's just trying to survive, much like you.