The story begins to unfold on the first day of Harry Potter's third school year, at Kings Cross. Hogwarts pupil Lavender Brown is brought to the train station by her Muggle aunt. Because Emily normally lives in France and has no clue that her niece is a witch, she is not very amused by that fact. It seems like an accident in the chaos at the gate that 'Didi' (that's the nickname Emily calls her sometimes) forgets her suitcase, so that the red haired woman has to carry it into the train and go looking for her. Eventually the train departs and the Muggle is still on board. There is nothing she can do other than to sit down next to the person who caused this situation and to hope that she can travel back to London the same day. When the Dementors enter the Hogwarts Express searching for Sirius Black, the new teacher for Defense against the Dark Arts is casting the patronus charm. While he's checking the whole train, he finds another adult in it and does at first not know what to do with her. It should be impossible for an unknowing Muggle to be on the train without anyone noticing, so it seems that something has gone wrong with the security spells and he decides to take her to the headmaster as soon as they arrive at the castle. Remus shows her to a classroom and asks her to wait, for he will get Dumbledore as soon as he can. While he is at the feast, Emily is too curious to stay where she was told and is wandering around the corridors.
As a historian she's just asking herself by whom this castle was built and in what century when she is nearly scared to death by a tall dark man standing right behind her. Of course this is the Potions master of the school who has seen a flash of red hair trough the windows of the Great Hall. When he realizes what she is and that she is not willing to take orders from him, he threatens her by hexing her legs together. They go to Dumbledore's office where they both hear things that they don't want to.
Emily ends up staying in Snape's flat in an extra room for herself, because it is too mysterious that the security charms didn't work. The ministry thinks that Sirius Black might be behind that and until it's not clear, she will have to stay at the school for her own safety. Snape on the other hand is not amused about the fact that a Muggle woman he hates has to live with him. At least she accepts during her second day that she's really in a magical world, when Aurora Sinistra takes her to Hogsmeade. The women go shopping and the professor answers every question that Emily has. Coming back in the evening, she wants to apologize to Snape that she laughed at him, when she was thinking that all of this was just a big Halloween Party. But he's not in his best mood after the first day of teaching. He starts an argument about the house of Slytherin and if she would know what she meant to him, the Head of his house. But Emily isn't the type of woman that is taken aback by that. Hmm if that is so, professor... If you act up like that, you can surely say proudly to me that you are a pure blood through and through and that this is the reason why you call me a Muggle instead of using my name!?" Of course in this point he first lies to her, but she doesn't seem to believe him.
As if she could see that he wasn't telling the truth...
In the following weeks the two are fighting even more and all the time. Severus is as unfriendly and sarcastic as he can be, just to get rid of her and she on the other side is stubborn and strikes back, what makes him even more furious. Nearly every other day he complains about her and asks the headmaster to put her with Minerva or Aurora. While the other teachers, especially Lupin, are doing well with her, Emily learns more and more about the world she's now in. The little house-elf Tink is by now her personal assistant and can be called by a little bell. While the redhead tries to kill time by reading, Snape gets more and more the impression that she's just mocking him. That she and Remus would work together just to help Black. It doesn't help to calm him down when everywhere in the castle the rumours about him and Emily as a pair spread. This is the only explanation the pupils can accept for the fact that she lives with that bat, without getting mad or completely scared.
An incident with a mysterious love letter sent by Fred and George Weasley isn't helpful at all and he tries to frighten her a bit when he shoves her surprisingly in a corridor. That's the moment between them when Emily falls silently in love with him, while he is still hating her more and more. For him it is clear that she is enjoying to take center stage with her too short skirts and high shoes. But after the Halloween night, where Sirius Black breaks into Hogwarts, she begins to reduce her own sarcasm when she's arguing with him. Snape on the other side has to rethink his theories and discovers that she can be acceptable company in the evenings. In public he keeps up arguing with her and in the evenings he accepts it, to be a conversational partner and a mentor to her. It looks like they both make the best out of their situation stuck together. They even go down to the village and have a drink together at the three broomsticks. A bit tipsy she starts questioning him on their way back to the castle, about what kind of women he likes, or which feature is the most important to him. She does not get anything really informative from him.
Only much later, she becomes aware of the fact that he hates Christmas and everything around it. Luckily she isn't much for decoration either. So the Christmas eve comes and goes as the new year does. After he received a present from her on December 25th (and not only he should get one from her, for example Arthur Weasley received a Game Boy with the game tetris ) and on January the 9th for his birthday (in our rpg he's now 48, because of his appearance in the movies. Alan Rickman wasn't the youngest after all ) he's expecting nothing bad to happen until the end of the winter holidays.
Preparing himself to get started with school the next day, he's brewing a love potion while Emily enters his room. By sheer accident she pushes him right into the potion and has to deal with the result: A completely love-fooled Snape, which scares her more than his usual behaviour. With the words: Emily, my love did you get hurt?" a very long night begins. Every advance of him she turns down and tries to escape and get help from outside. But he doesn't let her out of his office, instead he tricks her into going back to their rooms. Like a true 'charmer' he plays music, offers her to dance and sings (he's very out of the tune) for her. The red fox is on the other side still aware that all of this is caused by the potion and that he wouldn't do one these things by free will. It's still hard for her to turn everything down, even a kiss. Best method: Buying more time by talking. In the end she can't hold him and herself back any longer and they end up in his bed. After calming down a bit, but still under the influence of the Armotentia, Snape tells her about his dark mark, the Death Eaters and that he killed his father and of course the name Lily is falling, too. Under silent tears she has to admit that this whole evening was a mistake, that his love is not true and that she is lying in the arms of a maybe murderer.
When he awakes on the next morning, Severus has no memories of the night and is afraid that he might have raped the woman next to him. Emily assures him that it wasn't against her will before she hastily flees the room. During the day she feels even more guilty and he becomes angrier and angrier. At the end of it, he's got himself convinced that this wasn't an accident, but a well played trick on him to bash his privacy, that she couldn't be an exception from the mass of people that humiliated him.
In the following weeks they barely talk to each other, Emily is not allowed to stay in the same room with him, they are not even arguing on their way to the Great Hall for the meals. Still, she's not willing to move to someone others' quarters. She loves him nonetheless and tries to find out more about his past, about Voldemort and what he meant when he told her about murdering his father. It couldn't be possible that he really killed someone and was still a teacher at Hogwarts. Two months later, Dumbledore calls the young woman to his office and helps her understand. After a while he starts with the words: Once there was a very pitiful boy at this school that was very intelligent and gifted, but he felt like a delinquent because of his father. He was a Muggle and disapproved everything magical, even his wife and son." The headmaster tells her about the fact that the mother of spoken boy was always hit by her husband until he one day overdid it and was killed in the heat of the moment by his own son.
With this he wanted to explain Emily how it came that he himself defended Snape during his trial and that he was now working at Hogwarts.
On the other side, Remus tries to help her in other ways and wants to talk to Severus. But he doesn't get far and they only argue about that Muggle. With the werewolf defending her, it just seems clearer for the black haired professor that these two are working together and against him. Even the reminder that once he was the boy seeking for forgiveness and should know how Emily feels, isn't working the right way, for he snaps and threatens Lupin with his wand to shut up. After that encounter he leaves the castle and apparates to Godric's Hollow. It's the anniversary of the day he sealed Lilys death sentence by hearing a part of a certain prophecy. (I didn't recall if there was a special date for this day, I just remembered that it was cold and wet. So maybe it was in fall and not in spring...) This is his day of the year to come back to her grave and grieve for his lost love. After spending nearly the whole night out in the snow he returns to Spinner's End and stays for the weekend there alone, thinking about his past, but also about him being at loggerheads with Emily. A very strange dream bothers him, too and it's nearly midnight when he returns to school, without any logical sounding answers. What he finds is a sleeping young woman waiting for him, whom he lifts and carries to her bedroom.
The day after that he wants to find out whether it would be worth it to give her the second chance that he never got. He needs to know her reason for simply caving in to his advances on that special night where he wasn't himself. But he doesn't find it, just that Emily won't say what he has to do or must not do. According to her, she wishes to have more contact again, but it would be still his own choice. Also she confesses to him that she was weak on that night, weak and that she really 'likes' him. Alone in his living room he begins thinking again. All of her efforts were too much work if she were simply mean and tried to trick him. She must really hate him by heart to go trough all the works... or, maybe, she said the truth and actually likes him. Still unsure about her, he declares a truce between them. It seems like he's only waiting for her making the next mistake. And it shall come.
But first it happens that Sirius is back in the school and Severus can't deny that he worries about Emily's safety. With this incident, new security regulations all over the castle are enforced and the Muggle is no longer allowed to walk alone.
She ends up spending most of her time in classes with the pupils, most of them of course in the dungeons, where she is allowed to observe the first to third years. She proves that her theoretical knowledge is good but then she makes another mistake by helping Ron. Besides his headache and that Potter was seen in Hogsmeade, without any consequences for him, this betrayal of his trust in Emi was enough to make Snape explode again. But it's not only him who has already been testy all day and they again spend the evening arguing. While Snape feels once more betrayed, even more because he allowed her to massage him some evenings before, she thinks that he never really trusted her one bit. In the end, she loses control and says something very stupid: Do you treat your secret 'friend' like that, too? That one you visited that weekend? A friend I can imagine myself who she is... what was she called... what was that name again, you told me... Lily?"
In the next second a wave of magic slams her back into the wall, holds her in place, strangling her, while Snape is coming closer. He's so inflamed with rage that he doesn't even need a wand (like Harry didn't when he hexed his aunt Marge). LILY is taboo for YOU! YOU listen? NEVER EVER you will utter that name again! A filthy Muggle like you has not the right to do that!" He lets her down and while she's coughing and gasping for air he grabs her hard by the chin. If you overdo one more time, then Sirius Black will be just a minor problem. Then I will kill you by myself!"
It should be the first time of her life that she is really afraid of him and takes his threat seriously. He could do it and probably he would do it. So it's not surprising when she stays in her room over the weekend and doesn't want to come near him, without being forced. But unfortunately she has to bring a book back to the library and she has to fetch it from his study rooms, where he's working at that moment. After all the troubles he had with her, Snape tries to distract himself by brewing. A complicated and dangerous potion is bubbling in his cauldron when he sees something moving in the corner of his eye. With that he accidentally let more drops of Thestral saliva into the potion than needed and he only has time to turn around and try to protect the woman from the explosion. Injured he collapses and sends her off, to leave him alone. While Snape tries to get up, so he can treat his own wounds, she doesn't obey his orders. On the contrary, she enters his sleeping room to fetch a pain soothing potion for him to help him up. He doesn't like the idea that she is helping him and should treat his injuries, but the fabric of his coat has burned himself into his flesh. And his only other choice would be Poppy and some time in the Hospital Wing, which is not really an option for him. After this torture he fells asleep and is dreaming again about himself as an 8 year old boy in the church next to his devout father and about his mother treating him after he was beaten up again by his old man. When you don't know what you've done wrong, then I can't help you. Then, Severus, you are doomed."
When he wakes up, he's still in terrible pain and wonders why Emily is sleeping next to his bed. But he has not much time, for he has to start his daily routine. Teaching is difficult with his back still hurt and so he's feeling very exhausted when the last pupil clears out of the dungeon and tries to relax with some music he knows from his childhood, church singing. His guest insists after that, staying for another night and when he wakes up the next morning, he sees her the first time without make-up. It seems like he really sees her beauty as a woman for the first time. She always spent a lot of time in the morning on her hair and make-up, but now she looked a lot more natural. He likes this more than the puppet-like face she wears every day but Severus doesn't dare say a word.
In the afternoon he asks for her help, brewing the wolfsbane potion. With this he explains her, that her friend is indeed a werewolf. But she's not as shocked about that, as he would have expected, but a lot more about the fact how bad these people are normally treated by other witches and wizards.
The exams of the pupils are coming closer and closer, too. Snape has healed up completely and is again trusting her a bit more than others, allowing her to massage him more intensively and helping him with the preparations for the exams and another wolfsbane potion for Remus. It looks like they could become friends when the ministry announces that they haven't found anything abnormal. As a result, Emily will be sent back home at the end of the school year with the pupils on the Hogwarts Express. So it's not his best last week in the light of her leaving Hogwarts and the magical community behind, when the incident with Black happens. (At this point of the story, I mixed up book and movie and a bit of my own fantasy) So Snape gets knocked out in the Shrieking Shag by three Expelliarmus spells but awakes the second when Lupin has transformed. He protects the three children and gets attacked by the werewolf himself. But when Harry runs off to follow Sirius, he can't get after him, because the Dementors are coming. So he shields Ron and Hermione with his patronus while holding them down. But his doe gets weaker and weaker under the attack of so many enemies. His happiest memory of Lily isn't strong enough anymore and he has to think of Emily. What she would do when he wouldn't come back, what she will miss when he's no longer around her. So he remembers the happier moments he spent with her and his patronus becomes again more powerful to ward off the Dementors. (After that it follows the storyline of the book, so Snape is really pissed off when he comes back in the morning) He doesn't tell her every little detail about his rough night and withdraws from her the last two days. He can't stand to be near her, when he knows that she will leave anyways.
What he doesn't know is that Dumbledore has made her a job offer. She could return to the school as a teacher for Muggle History, her own field of expertise, but she's unsure if Snape would tolerate her for another year inside the castle. The moment Albus tells her that he's sure the potions master would indeed miss her, she accepts. He quotes him: If it must be, then I would allow her to stay in her room."
The young woman knows as good as the old wizard that him saying such things meant more than someone would expect first. The plan is that she will go back to France along with Arthur Weasley and clear up everything according to her job in Versailles and her flat there. At the end of the summer, she will come back to England.
Severus hears at the same time something very interesting from the talkative house-elf Tink, that her master would be unhappy to go and that she likes him very much. But he has no time to think about that, because Remus is waiting in his office for one last talk. He tries to excuse himself for the events of last night, but more than that he tries to make clear how much Emily would miss Snape. As a friend of her he had this silent impression that she has fallen in love with her host. Yes, everyone should be where he belongs. As she belongs here and to you. I hope it will not cost you another year to realize what luck you have in that woman."
At last, most people realize what they had when it's not present anymore. So Emily departs from Severus and follows the plan, going back to France over the summer holidays.
He never expected that he would really miss her that hard. But he's mostly a creature of habit and during that last year, she became one of his habits. So he has to admit that she became a friend to him. A person he could talk to and be sure that his worries wouldn't be the topic in the Great Hall the next morning.
In another land Emily has her hands full of work, not only because she has to face her superior again, who thought she had been taken as a hostage, but because of her friend Arthur. She shows him Paris and Versailles, but mostly she shows him the Muggle world. So he's like a little kid in Wonderland. But during her time back home, she writes a letter to Severus and attaches a photo of herself taken by Arthur. It's not like she expects him to keep it, but wanted to show him a bit of the beauty of the garden at the Palais des Tuileries. He never answers.
However she quits her old job and is on her way back to her true home, Hogwarts, in the dungeons with her dear professor. What she can't know is that, in the meantime, he has had a wet dream about her, and, as if this wasn't bad enough, her image keeps invading his mind, too, when he touches himself. He feels ashamed because of that and like he is betraying their friendship, so he decides that he would forget about that, call it quits with her remembering the night of the love-potion and move on.
But that doesn't turn out to be that easy when he apparates to London to collect her from Kings Cross, where she directly jumps into his hands. In order to not let her fall down, he grasps her behind. He never expected their reunion to be that wild!
But after she calms down a bit and after telling him maybe a hundred times how happy she was to be with him again, they go to Diagon Alley. They both would need money and he is planing to give her a present. A cloak like wizards and witches are wearing it, in black silk with golden embroidery showing the fleur-de-lis. With that he hits the mark and they go back to Hogwarts.
With the words: Have you received my letter?", the first chapter ends.