Rose and Savin's fourth year included a number of notable events, ones generally more pleasant than those from the year before. The most important, as far as most of the student body was concerned, was the decision to host a Yule Ball at Hogwarts. As the Headmaster explained to the excited students one night partway through the fall semester, the Yule Ball was traditionally part of the Triwizard Tournament, which had not been held for over one hundred years. However, after nearly five years of peace since the defeat of Voldemort, even the Hogwarts faculty needed little excuse to host a celebration, and were experimenting with the idea of a Yule Ball at Hogwarts even in the absence of a tournament. Unsurprisingly, most of the students were quite excited by the idea, and immediately began plotting and planning how to make the most of the occasion, whether simply viewing it as an excuse to dress up and party or, particularly among the older students, seeing it either as an opportunity to advertise who was dating who or a chance to publicly declare affection in hopes that it might be returned.
Rose and Savin, while managing to avoid much of the drama and pageantry that often goes along with such decisions, decided fairly quickly that they would attend the ball together, and after some deliberation and discussion finally admitted to themselves that maybe they were going as a bit more than just friends. Snape, though secretly quite pleased that his favorite students were getting together officially like this, nonetheless became somewhat panicked when the implications began to sink in, particularly when he remembered that while Savin might still be just a favorite student, Rose was now more than that. This panic was not, as many parents might have felt, a concern that his daughter was growing up, hanging out with a boy, and potentially getting into who knew what kind of mischief behind closed doors, but instead a more practical concern. As far as he knew, Rose owned no dress robes, and despite the horror that filled him at the thought of trying to take her shopping, he did not want her to have to attend the ball in her school robes or a muggle dress (though he wasn't entirely sure she had any muggle clothes fancy enough for this sort of thing anyway). He could remember well from his own school days the embarrassment of being invited to a party by a roommate, and facing the choice of showing up in his school robes to a formal event or admitting he had nothing to wear and asking for help. In the end his solution had been declining the invitation altogether, which did little to avoid embarrassment since he was fairly sure all of his rich pureblooded "friends" knew exactly why he didn't attend.
After a surprisingly long time pacing his office and trying to consider all his options, Snape gave in and went to ask Professor McGonagall for help. He knocked on her door one evening, and upon being invited in and offered tea, sat awkwardly twisting his fingers together and struggling to find the right words to say. After a few aborted attempts, she finally told him firmly to either spit it out or leave and let her get on with her grading. Faced with an impending loss of help with the matter, he blurted out that he didn't know how to go about getting Rose dress robes for the ball, and wondered if she might be able to help in some way. McGonagall agreed immediately, though not without chiding him a little for not coming to her sooner and for doubting that she would be willing to help, though internally she was rather touched not only by his thoughtfulness towards Rose, but also by the idea that the generally standoffish Potions Master felt comfortable enough to come to her for help on such a matter, however awkward he clearly felt about it.
The next day Professor McGonagall pulled Rose aside to quietly ask if she would like any help picking out something to wear for the ball, mentioning casually that Professor Snape had given her permission to take Rose into Hogsmeade to look if she wanted. Rose, who hadn't even considered that she needed dress robes, and had little idea of how to go about obtaining them, let alone what sort of thing would be appropriate to wear for the occasion, accepted the offer eagerly. Though later, when telling Savin about the shopping trip and the conversation that had preceded it, she did admit that there was something a little awkward about going dress shopping with your professor, and even odder to see Professor McGonagall comparing different fabrics and talking about what trim might look nice or discussing the current fashion for dress robe sleeves and how it differed from when she had been a girl picking out her first robes. Savin acknowledged the point, but countered with a comment that it couldn't possibly have been as bad as if Snape had taken her himself, which she wholeheartedly agreed with, both children suddenly struck with the horribly odd image of Professor Snape examining lace trimmings with the same intense scrutiny that he used for potions ingredients.
When the evening of the ball finally arrived, both Snape and McGonagall were watching from the side of the hall as Rose came down the stairs to meet Savin. She was dressed in flowing robes made of different shades of gold and orangey-red, making her almost appear to be clothed in warm flames and bringing out the gold in her eyes. She had pulled part of her hair back away from her face, but still ducked her head slightly when she saw Savin, as if expecting it to fall forward and cover her shy smile as it usually would have. He was waiting at the bottom of the stairs for her, not bothering at all to hide his bright grin when he saw her. Savin had brought a white rose for her hair, but whispered a quick spell to change it to a golden color before helping her tuck it into her hair above her ear. He bowed, offering his arm with all the poise and formality brought about by years of etiquette training. Rose giggled a little, ducking her head again before taking his arm and allowing Savin to escort her into the Great Hall. Watching the pair enter the ball together, both of their Heads of House found themselves silently remembering another Slytherin-Gryffindor couple with one redhead and one dark who hadn't made it to a Yule Ball together, and hoping, as they watched Rose and Savin twirl together on the dance floor and laugh as her fiery skirts swirled around them, that this pair might have more success than the other.
The other main event (or series of events) that made that year notable was that Rose and Savin convinced Professor Snape to give them private lessons throughout the year. It began as a fairly informal thing, with the professor inviting Rose to his quarters for tea and conversation, an invitation that was quickly extended to Savin as well. Since all three were far more interested in discussing magical theory or advanced spellwork than the weather or recent Quidditch scores, casual afternoon tea soon became more academic in nature, with Snape often recommending journals or books to the students and then discussing the more complicated parts with them. None of them could exactly recreate the conversation in which Snape agreed to teach Rose and Savin how to produce a patronus charm, though the professor was fairly sure it had involved one of the teenagers admitting that the pair was investigating how to perform the spell on their own, though in hindsight he had to admit that it might have been slightly more responsible of him to tell them to stop rather than offering to help.
However it had come to be, Rose and Savin spent a large portion of their fourth year studying the spell under his guidance, and by the spring both were able to produce corporeal patronuses and send messages with them. Rose's patronus took the shape of a small cat, and Savin's of a fox. They couldn't practice the charm on actual dementors, of course, but since none of them really expected to ever encounter dementors they didn't consider that much of a problem. Rose and Savin were mostly interested in the patronus charm because it was considered a complex and difficult spell and therefore was an interesting challenge, with the message sending capabilities as an added bonus. Neither mentioned this to Snape, fairly sure they knew exactly what his reaction would be and that it would not be pretty, but both of them were also interested in patronuses for another reason. The first time Rose had come across a mention of the spell (Savin had already heard reference to it before) had been in a book about animagi, a reference to the idea that for most animagi the animal form that they took was the same as the form of their patronus. Since Rose and Savin had already discussed wanting to become animagi someday (with the implication that "someday" should be sooner rather than later), this led to their desire to learn the patronus charm in hopes that it would give them a heads up about what their potential animagus forms might be. They likely would have been happy with being able to produce patronuses whatever the form, but were especially pleased that their cat and fox would likely make good animagus forms as well, if and when they figured out how to do that transformation.
And indeed, in addition to all of their regular coursework, the beginning preparations for OWL exams, and all the other independent research projects that they were still working on, during their fifth year at Hogwarts Rose and Savin began their studies to become animagi. They originally planned to pursue it on their own, using a combination of general information found in the main section of the Hogwarts library, more specific information gotten from the Restricted Section (with dubious permission from that year's Defense Against the Dark Arts professor, who thought they were writing a historical research paper on how regulations of various magical arts, including animagi, had changed over time), and a few books that Savin had borrowed from the library in Silther Manor, which had quite a few books that weren't always easy to find in other places due to restrictions.
These plans were changed when Snape caught Rose with one of the books, a very old one from Silther Manor which had nothing in it other than instructions on how to become an animagus, instructions which Snape said were actually very outdated and a much more difficult and dangerous way to go through the process than what was used now. Fully aware that simply taking the books away from them, giving them a talking to, and/or punishing them was unlikely to really stop Rose and Savin from trying to do this, Snape instead approached Professor McGonagall about giving them lessons, something which she was both practically and legally qualified to do. As he explained to the initially skeptical professor, if they didn't help the children learn, the little idiots would probably go off and kill themselves trying to do it on their own. Though McGonagall was not at all impressed that Rose and Savin had been planning on studying animagus transformation on their own, something which was not only dangerous but also illegal, she couldn't deny that they had the requisite magical ability and drive, or that Snape was probably right about they finding another way to accomplish their goal if denied help. So, after making it very clear to both students that they were never to attempt anything like this on their own, and that if she ever got wind of them doing anything illegal again she would turn them in no matter what Snape wanted, Professor McGonagall began helping them learn how to be animagi. By the end of their fifth year, Rose and Savin were registered animagi, the youngest to ever be registered (if not necessarily the youngest to successfully achieve the transformation). As they had suspected based on their patronuses, Rose took the form of a small black cat with golden eyes, while Savin became a fox with reddish-brown fur the exact color of his hair.
It was also towards the end of fifth year, around the same time that they completed their animagus studies, that Rose and Savin finally acknowledged what had been obvious to their mentors for several years already (even Snape, who wasn't necessarily known for his powers of perception in these sorts of matters), and began dating officially, and at least somewhat publicly. Savin was popular (or powerful) enough in Slytherin to get away with dating a muggleborn, even a muggleborn Gryffindor, and Rose cared about as much for her House's unease with her choice of boyfriend as she ever had about Gryffindor's thought on anything she did. It wasn't as though they hadn't been dealing with backlash over their friendship for five years, and after so long most of the student body (those who even noticed enough to have any thoughts on the matter) were used to Rose and Savin's friendship enough that they barely noticed that friendship becoming anything more. Even during fourth year when they had attended the short-lived Yule Ball together (after the professors had been reminded how unpleasant it was to chaperone teenagers at a ball they had made the Headmaster promise not to make it an annual event, and the experiment was not repeated for many years), most of the students had been too caught up in their own dramas to pay too much attention to a pair of students that most cared little about. But while most of Hogwarts may have known of the changing relationship between Rose and Savin, and Snape in particular was quite pleased with the state of affairs, both as Rose's father and as both of the students' mentor, Savin's parents were kept purposely in the dark. All involved were aware that "displeased" would be a major understatement whenever the Lord and Lady Silther did finally find out that their son and heir was dating a muggleborn, and hoped to avoid the issue as long as possible.
Fifth year ended, with OWL exams that both Rose and Savin passed with flying colors, and after another pleasant summer at Spinner's End for Rose and Snape and a slightly more tense one for Savin at Silther Manor, the pair returned for their penultimate year at Hogwarts. With their animagus studies complete, they refocused their extracurricular research attention on some spellcrafting work which they had begun toying with years before, after first confirming with both Snape and McGonagall that there wasn't anything even potentially illegal in what they were doing (neither was eager for a repeat of the lecture that they had gotten from McGonagall during those initial animagus discussions). Their biggest achievement was developing a sort of living gold flame which could be used for different purposes depending on how it was shaped. Their first permanent creations made with the stuff were jewelry, created from the golden flame-like material with a thin outer shell that felt almost like glass or crystal.
They made necklaces for themselves first, each consisting of a pendant of golden flames shifting within their clear shell, engraved with its owner's patronus form and initials, meant to be worn on a chain or cord. The main purpose of these paired pendants was to give the wearer of one a vague sense of the status of the wearer of the other. They continued to fine-tune the abilities, making them more accurate and able to convey information, but even from the beginning they could give a general sense of mood or emotion, and could be used to help locate the matching pendant or send a message like those that could be sent with a patronus charm (which of course was where they got the idea from). After completing their own, they went on to make an additional necklace which they gave as a present to Professor Snape, a flat pendant which he could wear unnoticed, tucked into the front of his robes. That one was less tightly tied to the others, and couldn't give as much information. As they were originally developing it, it was a source of frustration that they couldn't extend the same linking properties of two pieces to three, but ultimately they decided that wasn't necessarily a bad thing. After all, having a necklace that could tell your boyfriend how you were feeling was one thing, knowing that it was also relaying the same information to your father was a little different. But the necklace for Snape was able to tell him if either Rose or Savin was hurt and could be used to send messages like those between the two necklaces, and that was impressive enough.
Sixth year passed quickly, and seventh, in a blur of courses, exams, research, and even a little bit of free time. Soon the end of seventh year and graduation loomed ahead, and it was time for finalizing future plans of both the professional and personal natures. As far as professional futures went, Savin's parents wanted him to get a job at the Ministry, which they saw as a suitable and proper profession until it came time for him to take a more active role in the running of the Silther estate, and offered to use their many connections to secure him a post. They also began dropping hints in their letters about helping him find a nice girl to settle down with, listing off suggestions of young ladies they (mostly Lady Silther) would be happy to set up a meeting with. The boy (who perhaps must soon be called a man) was instead working to secure an apprenticeship at Gringotts working with their magical artificers, with eventual hopes to branch out on his own as an inventor and craftsman. While Rose enjoyed the magical craftsmanship that they had worked on together at school nearly as much as he did, her longer term interests lay with potions, and she intended to pursue a mastery in that subject. She, in a move declared by Savin to be rather Slytherin of her, had no issue with allowing Snape to give her a reference to an old potions master who worked in more obscure research topics off an alley near Diagon.
On the personal side, as spring moved towards summer in their last year of school and the end of their time at Hogwarts loomed ever nearer, Savin proposed to Rose under the tree by the lake where they had spent so many days together, and she (to no one's surprise) accepted. Savin had made the engagement ring, made as a twisted half in order to let it combine with an eventual wedding band, was made of the same golden flame material that they had created together. There were two flat stones inset into it, one the amber color of Rose's eyes and the other Savin's bright blue. Though they told Snape about the engagement immediately, Savin decided to hold off on telling his parents about the arrangement until he could do it in person. After all, telling your parents that you were marrying a girl they didn't know and would wholly disapprove of was not something to do by letter, especially when you suspected such an announcement would result in your disownment. And indeed, when Savin did inform his parents of his future plans, future job, and future wife after returning home at the end of the year, Lord and Lady Silther banished him from their manor, disowned and disinherited him completely, and told him they had no desire to see him ever again.