Harry was greatly disappointed by his DADA teacher. The man seemed concerned only with his own appearance and fame, but seemed to lack any knowledge in the subject he was supposed to teach. His books were just tales of his heroic deeds, that Harry and Hermione considered to be pure fiction. They even found some severe inconsistencies between the books and most of the spells mentioned in them were either fake or had very different effects than described. They really hoped that the parents were doing something to replace him.
It was a few weeks after he initiated the campaign to replace that teacher when he noticed Lockhart missing breakfast. The smiling professor was usually very punctual for meals, so his absence was noticeable. At the end of breakfast, Dumbledore stood up and spoke. "I'm sorry to inform you that professor Lockhart had to leave school due to some unexpected family crisis. For the rest of the week, DADA lessons will be free periods. You should still spend them usefully. Starting next week, I hope to bring you a new teacher to take that position. As for the books, I was informed by Flourish and Blotts that every student who wishes so may return the books in good condition and get a full refund. When we get a new teacher, we'll make sure to supply the appropriate books at discount price. That's all for now."
Harry got a letter from his aunt a day later.
"Dear Harry,
I was a bit upset at learning that your teacher was so bad that you felt a need to remove him. It still infuriated me that Dumbledore even considered letting such a fraud, as you've described him, teach at school. I've contacted the Grangers and they contacted some more people. Eventually, we all sent our letters simultaneously. Some of the magical folks even sent him howlers – I suppose you already know what they are.
I've just got the official response from the school, stating that the teacher was sacked and his books may be returned to the shop for a refund. I hope that whoever comes next will be a better teacher.
Now, I also remember you telling me about two more teachers who are useless. Shouldn't we try to replace them too? I hate to think of the money your parents left for your tuition being spent on useless lessons.
Love, your aunt Petunia."
He let Hermione read the letter. "Shouldn't we try to also replace the other two?"
She considered his question. "Maybe we should, but not right now. Once we get a decent DADA professor, we may start working on the Potions one. Actually, I'm sure that Professor Snape is very knowledgeable in Potions. I only wish he was better at passing his knowledge."
Harry could easily agree with that.
Harry didn't know who would be the new professor and didn't really think about it. He didn't know enough people in the magical world to even have an opinion about that. He still told Sirius and Remus about that, when they visited during the next weekend, as had become their custom since the previous year.
Remus just nodded understandingly before Hermione grabbed his attention with some questions.
"I think we should change our visit schedule," Sirius told him, a short while later.
"Why? What's wrong with visiting during the weekends?"
Sirius faked thinking hard. "Well, that would force me to leave the castle and come back for a visit, and then leave and return to my apartment at the castle."
It took Harry a moment to catch up. "You're going to stay here all week? How come?"
"You've rid the school of an incompetent DADA teacher, didn't you? Now you need another teacher, and it so happened that I had nothing to occupy my time for the next few months," Sirius answered nonchalantly.
"You're our new teacher?! Wow! I'll now have to call you Professor Black, won't I?"
Sirius smiled. "In class and other public venues – of course. I'm still Sirius for you and Hermione in private."
Hermione, who was discussing something with Remus, didn't even notice until Harry got excited. "What was it?" she asked.
Sirius turned to her and pompously recited, "Let me introduce your new DADA teacher, Professor Black."
It was Hermione's turn to gasp, but then she turned just a bit mischievous. "I hope you prove to be a decent teacher, or we'll have to drive you away too."
Sirius faked being hurt. "Oh, don't you trust the Black sheep to prove a decent teacher?"
She smiled benignly. "We'll see in class."
Harry thought for a moment and turned a bit worried. "What about the rumoured curse on that position? Maybe you should make sure it's removed if you intend to keep that job."
The older man stopped joking. "I've talked to Dumbledore about that. He doesn't believe there is such a curse and isn't ready to spend the school's limited funds on that, especially after having to deal with the Lockhart fiasco. I decided to hire a team of curse breakers and check as thoroughly as humanly possible. I can afford the expenses."
Harry nodded appreciatively. "I hope you can find and remove it. I'd like you to teach us." He then thought for another moment. "Actually, you said that Remus is even better. Why didn't he get an offer? Not that I think you're not good enough."
Sirius smiled sadly. "I would have also recommended him, but he just can't accept such a job. He may tell you why when you're a bit older." He gave Remus a look that clearly meant, "Keep quiet now!"
That evening, after most everybody was at dinner, Dumbledore stood up. "As you remember, I promised to find a new Defence teacher and I did. Please welcome Professor Black, your new teacher."
The side door opened and Sirius came in, wearing high-quality robes, smiling and waving at the students. Only a few clapped their hands, most enthusiastic were Harry and Hermione, of course. Evidently, Snape was much less enthusiastic. In fact, he looked angry and ready to hex somebody, if only he could find an excuse.
Dumbledore waited for Sirius to take his place at the table and then lifted his hands for quiet. "Professor Black has taken more than a week to accept my offer, since he wasn't sure he was good enough and wanted to reread all the course material before agreeing. This alone speaks highly of his dedication and of the seriousness with which he takes his job. I should also mention that he used to be an Auror before he was wrongfully imprisoned. We all wish him success."
He waited for a moment and then added. "For many years, there were various rumours about curses placed on locations or positions throughout the school. Starting next week, a team of curse breakers is going to search the school meticulously to prove or disprove these rumours. They may also need to search the dorms. You will be informed of such searches as far ahead as possible. Please cooperate, so that we can all resume our normal routines as soon as possible."
\/\/\/
It was later that Sunday night, just after the new DADA professor introduction. Silky was leisurely sliding through the grass when she sensed movement. She turned in its direction and noticed a fat rat hurrying towards the gate. She sniffed the air. That was no rat at all. It was that man-rat and she could also sense that letting him go was dangerous, not by himself, but by the deeds he could later do. Snakes don't spend much time on thinking. Their instincts are simple: a danger should be eliminated, and if not possible – avoided. Silky had no problem eliminating that danger, but she didn't want to eat a rat that isn't a rat nor kill a man in the form of a rat. That didn't mean she couldn't alert the other snakes to the fat rodent.
A fat, lazy rat is no competition to a young snake. Silky quickly found two other snakes and directed them to the rat. Unlike cats, snakes don't play with their food. They just ambushed the rat not too far from the gate while Silky took her position closer to it, making sure the rat would not escape. It was then a matter of seconds. The snake closer to the rat bit it, inserting enough venom to immobilize it. Silky made sure this was the right rat and then left. How the two other snakes shared a meal was none of her business.
\/\/\/
Ron was very agitated the next morning. He kept looking for his rat until it was almost too late to go for breakfast. He then openly accused Hermione, "It's probably your cat that ate my rat. I saw some red hairs and red spots near my bed."
Hermione wouldn't take it. "My cat was in my room all through the weekend, since it doesn't like rainy weather. As for your 'signs' – are you sure you didn't see your own hair? It's red, if you haven't noticed, and I can see you have an injury on your left thumb. It could have stained your sheets."
"Oh, Scabbers was very agitated after dinner, when we were all talking about the new teacher. He bit my finger when I tried to grab him," Ron admitted
"Maybe he just ran away, finding the agitation too much to bear?" she suggested.
Ron just huffed, still unconvinced, but unable to prove his case.
That evening, after enjoying their first lesson with Sirius, Harry told him about the rat incident. Sirius became more interested than expected. "A rat, you say? How long had he been with the Weasleys?"
"About eleven years, I think," Harry said after giving it some thought. He then frowned. "Isn't that quite a long life for a rat?"
Sirius didn't reply. He just asked some more. "Was there anything in particular that you remember about that rat? Something to distinguish him from others, if we manage to find him?"
It was Hermione who answered. "He was missing a toe on his front paw."
Sirius turned pale. "Please join me after dinner. I'd like to take a copy of your memories of that rat and view them. I have some suspicions, but I need to first see if they have any basis."
They joined Sirius as soon as they finished eating. He led them to the headmaster's office, where he explained. "There's a very simple way to extract memories. You have to think of what memory you want to extract a copy of and bring it to the front of your mind. Then, by pressing a wand to your temple, you can tap that memory and pull it out. It can then be viewed in a pensive," he pointed at a large basin with various carvings on its surface that was sitting on one of the shelves in the office.
It went quite well. Sirius extracted the memories from both youngsters and then showed them how to use the pensive. Dumbledore only watched, not taking part in the conversation. They left the office as soon as they finished viewing their memories in the pensive, not hearing the conversation taking place there, after Dumbledore had a look at the memories as well.
It took another day until Hagrid happened to notice some scavengers near the gate. He noticed that they were attracted to the remains of a rat, but as soon as they came near enough to get a good sniff of its scent, they turned away. Bewildered by their behaviour, he wrapped the remains in a piece of cloth and brought them to Dumbledore. After he told his story to the headmaster, Dumbledore called Sirius and they both examined the remains. None of them had any doubt after a moment. The rat had been Peter Pettigrew. It was more difficult to asses the cause of death, but Dumbledore was able to use some obscure spells to find snake venom there.
"I think I can now understand what had probably happened," Sirius said.
Dumbledore nodded for him to continue.
"He probably didn't expect that I'd ever get free from Azkaban. My trial and its conclusion unsettled him quite a bit, but he thought that living with the Weasley and at Hogwarts was safe enough, since I've never been close to any Weasley and I wasn't known as a scholar. Finding I was going to stay at Hogwarts for an extended period has probably frightened him enough to make him try to flee. Doing that at night, in rat form, wasn't a very smart decision, so it seems. A snake caught him and killed him."
"But he wasn't eaten. Why would that be?" Dumbledore asked.
Sirius answered slowly, forming his thoughts into word as he spoke. "An animagus is not an animal. Under the animal form, it's still human flesh. It doesn't smell completely human, but it certainly doesn't smell like the animal should. That's why it wasn't eaten – it smelled wrong, and also smelled of snake venom. The scavengers didn't dare take a chance with it."
"Shouldn't we inform the pet's owner?" Dumbledore commented.
"Sure. He doesn't need to know it was actually a wizard, though. The stupid rat was bitten by a snake is all he needs to know," Sirius agreed.
Ron got the remains of his rat the next morning and Hagrid helped him bury them later that day. Despite being informed that a snake killed his rat, Ron didn't apologize. Neither Hermione nor Harry expected him to. They were quite happy to let him stay away from them.
I only have four more chapters written, but the story is far from finished. You may help me finish it by giving my muse some ideas which may hopefully wake her up. If I use your idea, I'll mention you in a comment at the head of the chapter. The rate I'll continue writing this story highly depends on your input.