Hey there, details are below
It was too easy. Barty had fooled that paranoid auror Moody when he'd stalked the older wizard and knocked him out with a stunner one night after a raid. It was almost surprising that he wasn't found out earlier; apparently that eye of his wasn't as all-seeing as he'd claimed it to be. After knocking the auror out, it was only a simple matter of tying him up and locking him in his own trunk. No one would ever look for Moody there.
The plan was ingenious, really, when Barty thought about it. Everyone knew of the man's habits and would thus expect him to use a personal flask. He was well known for his intolerance of things prepared by others, and Barty could understand that. Now with unlimited access to the person he was pretending to be, he'd have absolutely no need to worry about the polyjuice running out. All of the ingredients were readily available and all he needed to do was raid Snape's cupboard whenever he was running low. The auror's supposed strength had become his downfall. Each time he considered it, Barty couldn't help but grin.
Things didn't stop there. Not only had he caught and hid a prestigious auror known for sensing danger, but he'd done so under the nose of Albus Dumbledore. That man was the most influential wizard of the time with multiple positions of power, and Barty was the one lead him around by the nose. In front of all the combined staff and students of Hogwarts school no less. It was certainly a feat that he was proud of and would never allow himself to forget.
At first he felt partially paranoid himself, wondering if and when he'd be caught. But when that time never came he began to relax and sink further into his role. Barty didn't mind teaching that much, to his surprise. The students listened to him with rapt attention and asked good questions. He also liked the respect they gave him as he passed his students in the corridors. The shock on the fourth year students, especially Harry Potter, had been amusing to watch during his demonstrations.
With the entire school in the dark, it was mere child's play to place Harry's name in the Goblet and enter him into the Tournament. And he had almost unlimited access to the boy to guide him to the finish, just like his master wanted. A clue here, a friendly hint there, and the boy was given an easy advantage over his older competitors. He could hardly wait for the third trial to begin; all of his hard work over the year would finally be paid off when Harry touched the cup and port keyed himself straight to where his master would be waiting. The Dark Lord would be pleased with his efforts, of that Barty was sure. All he could do now was wait.
This was written for the March FanFiction Tournaments Competition, semi final - Hogwarts Professors.
Word count: 501