Harry was almost done with his detention, which was a good thing as it was nearing curfew. He'd even managed to see Snape inside one of the laboratories - Snape hadn't said a word to Harry, but he hadn't needed to, either. Harry'd seen from the slight tension of Snape's frame as he came in the door, that Snape knew perfectly well that he was there.
"Last batch." Harry stated clearly (leaving off the sir as they weren't completely in private. Harry descended the steps (for what seemed like the twentieth time, but which was actually the twenty-fourth. Harry'd gotten his second wind somewhere around the fifth, though, so it hadn't been as bad as it could have been.)**
As he left the room, Harry stared downward in horror, not at his feet (which where hopeless, not to mention soaked and starting to feel like they burned***), but at the staircase below. It was completely covered in mud - Harry'd somehow managed to hit the bannister even, and that was without using it!
The voice of experience in his head said, "This is going to take forever to clean." This was followed shortly by, "but at least I don't have to clean it."
Somehow, on Harry's way down, he'd managed to be near Filch's actual rooms (which, granted, he hadn't known where they were to avoid them) - at the exact moment that Filch emerged. Or, at least, tried to emerge.
Instead of actually emerging, he stood with his jaw dropped, and mouthed words that Harry was sure he shouldn't say. Heck, he was sure Filch shouldn't say them either. There might be firsties about, after all. Harry considered running, except... from personal experience, that would be taken as evidence of guilty, and Harry sure wasn't responsible for all this. He'd had orders, and he'd let Filch deal with the responsible party. Or, at least, that was the goal. Harry hoped to hell this worked, because the look on Filch's face strongly suggested he wouldn't be joking about thumbscrews this time.
Finally, Filch's mouth closed, and his burning eyes found Harry Potter. "Potter! Did you do this!"
"Yes, sir. My detention, sir." Harry Potter said, and Filch's spare, thin face reddened to the point of being brighter than Ron's hair.
**Harry is counting all trips. Snape's not having him do 80 "up to the top of Hogwarts" stair runs in a night.
***Frostbite is bad, kids. You can get frostbite in wet clothes a lot warmer than you'd think. That said, a bit of burning in your toes is probably chilblains, which suck but aren't "we'll cut your toes off." Read more somewhere else on the internet. General first aid is a lifesaver.
[a/n: da-duh-dun! Filch is the natural person to catch Harry (other people undoubtedly observed him completing the detention, but didn't say a word).]