October 1986

"As a Prefect, I should report you for wandering the corridors at this hour."

Charlie kept walking, ignoring the voice behind him. "As your favourite brother, you should grant me certain privileges."

"Where are you off to?"

"Nowhere."

"It looks to me like you're heading for the dungeon. If Snape catches you, he'll find an excuse to kick you off the Quidditch team. He knows Slytherin will beat us if we don't have you."

"Well, I just need to make sure I don't get caught then, don't I?"

The words were only just out of his mouth when the silhouette of Filch appeared at the end of the corridor. Bill grabbed his brother and yanked him into an empty classroom.

Filch clonked down the corridor, then stopped outside the classroom door.

"Has anyone ever told you that you walk really loudly, Bill? And coming from me, that's saying something. Got them, Charlie?"

The voice definitely didn't belong to Filch.

Charlie pulled two fat rats out of each pocket and handed them over.

"Password for the store cupboard is Murtlap. Heard him say it earlier."

"Brill. Keep watch for me, will you?"

Imposter Filch disappeared down the stairs into Snape's classroom. The Weasley brothers waited in silence until he returned five minutes later.

"Done?"

"Done."

"See you in Transfiguration."

"Night Charlie, night Bill."

Bill appeared deep in thought as they walked back to Gryffindor tower. "The escaped unicorns last week and the flooded bathroom the week before, was that you two as well?"

Charlie smiled. "What are you suggesting, dear brother? I am completely innocent. If you look closely, I think you'll find these are all the wrongdoings of the terribly conflicted Filch."

Meanwhile, in the corridor near the kitchens, after double checking that no one else was around, Nymphadora Tonks had just resumed her normal appearance. Well, it wouldn't do to have a middle aged Squib in the common room, would it?