February 12, 1994

Severus was waiting for it to be six in the afternoon, nervous.

In the corner, he had a half-brewed Temar healing potion, just in case, but who was he kidding? It was clear that the potion was nothing more than a stupid excuse.

Growling, he scolded himself. He was behaving as if he were doing something bad, and he wasn't, he was just going to teach a spell to a student.

Severus huffed nervously, running a hand through his hair.

He was going to teach a highly difficult charm to a twelve-year-old child, with him being the Potions professor and having a Defense Against the Dark Arts professor available who was clearly capable of teaching how to summon a Patronus.

Still, it was not forbidden. She had asked him for help, and he was the Head of her house, and it was his duty to help young Slytherins who needed it.

This was nothing personal.

Nor was it an attempt to prove to Lupin that he was the best Defense teacher.

Because obviously, he had no doubt about that.

For starters, Severus wasn't going to use any dementors. In the office there was nothing terrible that could scare Lily, on the contrary, a dose of Nightingale's potion burned gently in a diffuser, spreading the aroma of mint and ginger throughout the room. That was a relaxing atmosphere.

He was surprised that Dumbledore had given Lupin's plan the go-ahead. Severus hated Harry Potter with all his soul, but even he thought that making the brat repeatedly face a dementor to practice the charm was going too far.

It seemed like torture straight out of the darkest corners of Azkaban. But what could he expect from a werewolf from the Gryffindor house?

Just in time, Lily arrived at the office. The girl gave Temar's potion a mocking look, but said nothing. As a good Slytherin she understood the need for subterfuge.

Severus decided to get straight to the point.

"Miss White, if you haven't repented, I will try to teach you how to summon a Patronus. I warn you that it is a very difficult charm and that some magicians take years to master it. However, if you learn the basics of the enchantment, you will be able to create a corporeal Patronus when you are ready."

"I don't understand, Professor, aren't the Patronus always corporeal?"

"A Patronus is a force of energy that represents what dementors cannot destroy. Invoking them requires great magical and mental strength, and most of the time, the spell does not go well, and only a bright mist is generated."

"What shape are they, Professor?"

"When the Patronus is complete, it has the shape of an animal."

"What shape is yours, Professor?" Lily looked at him with her big bright dark eyes, waiting for an answer.

"That is a very intimate question, Miss White. The Patronus represents the most personal aspects of the person who invokes it," he scolded her severely, and she lowered her gaze, ashamed.

"I didn't know," she murmured apologetically. Severus cleared his throat and continued with his explanation.

"Each Patronus is unique and remains unchanged throughout our lives. Although it is also true that some events can cause a Patronus to change its form," he added, before realizing his mistake.

"What kind of events, sir?"

"Events that... make you grow as a person or substantially change what you are... or what makes you happy. For each person it is different, and as I have told you, this change is exceptional. Which is very convenient," he added, wishing to change the direction of the explanation, "because Patronuses can also be used as a means of communication, to carry messages. Because it is impossible to imitate another person's Patronus, it is a perfect way to ensure the reliability of the message."

Lily was staring at him with her mouth open, practically drinking in his words.

"Now, the spell is very simple, you just have to say Expecto Patronum, but the complicated part is inside your mind. To invoke a Patronus you must think of a memory that makes you happy, and transfer that feeling to the spell."

Lily nodded, but almost instantly frowned in a gesture he knew very well, indicating that she had a question.

"Professor, I don't understand one thing. To summon a Patronus you must think of something happy, but dementors make us remember horrible things..." Lily shuddered, remembering her encounter with the creatures. "How is it possible to think of something happy when they are around?"

"That is why the choice of the memory is the most important thing. It's not about thinking about how happy you were during breakfast, you must look for a memory that is etched in your mind, something that is basic to you, something that is important," Severus knew he should be more specific, but he was worried about giving away too much. "It can also be a person," he dared to say. "A friend... perhaps Miss Greengrass?" he suggested, after all, Astoria and Lily were always together.

To his relief, Lily did not ask him what he thought about, but nodded, her face very serious.

"I think I can try it," she announced, getting into position. She closed her eyes and took a deep breath, concentrating and inhaling the relaxing aroma of the potion. "Expecto Patronum."

Nothing happened, and Lily tried again, without success.

"What am I doing wrong?"

"The memory may not be strong enough. As I have already told you, you have to think of something that is important to you. Something that is immutable and that always makes you smile. That's why the spell is so complex."

Lily closed her eyes again, and this time she truly relaxed. Severus watched as she took her silver medal in one hand, concentrating.

And then, through the ring, a pleasant, warm, tickling sensation came to him. He was tempted to look into Lily's mind but stopped short. He had no right to invade her privacy like that.

And then, Lily moved her wand silently, and a silver mist billowed from the tip, floating faintly in front of her. Lily opened her eyes, and her joy was such that it broke her concentration and the mist disappeared.

"I did it! Something has come out!"

But Severus was focused on something else.

"Miss White, do you usually perform magic without saying the words aloud?"

She looked at him blankly, suddenly embarrassed.

"No... I do not know. I have not noticed."

Severus narrowed his eyes, assessing her. Suddenly, he seemed to see a diamond in the rough in front of him. What else could Lily do, without even being aware?

"In our little disagreement in November, you were able to defend yourself without saying the spell out loud," he recalled. "And now you have invoked a Patronus... or the beginning of a Patronus, without words. Do you know if it has happened to you more times?"

"I think... I think sometimes, Professor," she confessed in a low voice, again looking at the floor in shame. "Sometimes I concentrate better if I say the words inside my mind."

"Miss White, that is a sign of great magical power. It is a skill that is only developed after much training and is therefore only taught in preparation for NEWTs. You shouldn't feel ashamed of it, on the contrary, you should be proud," Lily looked at him with bright, open eyes, and Severus was tempted to smile, infected by her sudden joy. "However, I recommend practicing the spells out loud so that you learn the correct pronunciation and avoid accidents."

She almost rolled her eyes, already used to his habit of spoiling compliments, but it didn't erase her broad smile.

Full of energy, she continued practicing, managing to create a silver mist that grew larger and larger.

She hadn't yet managed to summon a corporeal Patronus, but Severus was still impressed. If she kept this up, Lily would be able to perfect the charm before the end of the year.

ooo

February 20, 1994

"Have you secured the protective spells?"

"Yes. If Black entered the dungeons, the alarms would ring immediately," Severus responded. "Have you heeded my warnings about Lupin?"

"I've heard you, Severus, but as I have repeatedly told you, I don't think Remus is helping Sirius Black."

Severus was going to give him a scathing response, but when they came across a group of students, he held his tongue. It was one thing to contradict the headmaster, and quite another to argue with him in public.

Almost by chance, he recognized Lily, and noticed that the student was greeting him with a smile. He responded with a curt nod but continued on without saying anything. However, Dumbledore noticed the exchange.

"I've noticed that Miss White seems more cheerful lately."

"Oh, really?" Severus protected himself with his usual irony but met the headmaster's penetrating and observant blue eyes.

"The private potions lessons seem to be working," Dumbledore hid a smile beneath his silver beard, and Severus frowned. He hadn't brewed a potion as an alibi since the first class with Lily, and somehow, he had the impression that Dumbledore knew what really happened in the dungeons, as always.

"The girl has talent," he simply replied.

"Really? I'm glad to hear that."

"Do you have any problem with it?" Severus faced him, wishing that the headmaster would tell him to his face whether he could continue instructing Lily or not.

"Not at all, Severus, I have always said that we must feed the minds of our students. And of course, you know better than anyone what is best for Miss White. After all, you are... the Head of her house," and with a discreet wink, Dumbledore walked away down the corridor, humming a cheerful melody.

ooo

May 2, 1994

Lily stood before him, wand raised and confident. She no longer needed to close her eyes or concentrate. Whatever her memory was, it was strong enough to make Severus' ring vibrate.

"Expecto Patronum!"

And then, it finally happened. Over the past few weeks, Lily had managed to summon an almost opaque mist, but that day there was no longer any doubt. The Patronus was corporeal, and the animal circled the office several times, jumping gracefully and illuminating the walls.

Severus gaped at her, unable to hide his astonishment, and for a fleeting moment, all his defenses collapsed, when he saw Lily reach out her hand to caress the silver head of her Patronus.

It was a doe. A silver doe.

And then Lily looked at him, smiling from ear to ear, her dark eyes shining, and Severus understood that that moment would be burned in his mind, as one of the happiest memories he had had in a long time.

ooo

July 20, 1994

Severus was sitting in the living room of his house, with the curtains closed and the candles lit to illuminate the room. In front of him, jumping gracefully, the silver doe kept him company.

He didn't know why he kept invoking her, but since the end of the course he had felt the need to see her almost daily.

Too many things had changed in too short a time. Apparently, Sirius Black was not the real culprit of the Potters' murder, but rather that other treacherous rat had sold out his best friends.

Not that the result was different. He had revealed the prophecy, and Lily Evans had paid the consequences for his actions.

And now, Dumbledore thought that the wizarding world might be in danger again, and that the Dark Lord might return.

And he, Severus, needed to remind himself why he was fighting. And that's why he invoked the doe, to look into her eyes and remember... remember that pair of green eyes that would never look at him again.

But now, every time he looked into the eyes of his Patronus, he also saw other eyes, round, dark and expressive. Eyes similar to his, but not entirely the same.

The image of the girl reaching out her hand toward the doe came back strongly to his mind. That had changed too. Severus could growl and protest all he wanted, but he could never fool himself. He and Lily White were also connected.

And she didn't know it, but he had changed too. He had started to worry about someone he had never wanted in his life. He didn't want to do it, he didn't want to have that weakness, or that responsibility, and he knew that the further away he was from her, the better it would be for both of them.

But he couldn't avoid her, she was his student after all. So, for the moment, Severus would just do his job, keeping his distance, and nothing more.

And yet, every time he looked at his Patronus, he couldn't make up his mind. Green eyes, black eyes, what was the difference?

...

There was no doubt in my head that Lily was going to have a doe Patronus. It is also no coincidence that she manages to invoke it on her birthday.

It seems that Severus is beginning to soften even though he doesn't want it.

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