The snow on the Scottish hills melted away with the spring, exposing the windswept land. The water in the puddles reflected the gray sky, dark clouds were coming from the West, foreshadowing an imminent snowfall. There was no hope for sunny days to thaw the icy lands.

Madam Pomfrey stepped away from the window, wrapped herself tighter in a yellow knitted shawl. Hermione had made it for her as a gift for Christmas. The mediwitch threw another log into the fireplace and hung her copper kettle, greening with age, from a hook over the fire. Minerva, who dropped in for evening tea, calmly checked the homework of the fifth-year students.

"Very well, Poppy, tell me, what could go wrong?" Minerva finally looked up at Poppy, after crossing out six sentences at once a boy named Scott's poorly researched essay.

"Everything could go wrong, Minerva!" Poppy cried, pursing her lips. "This is Severus we are talking about, you can never be sure when it comes to him!"

"Okay, shall we think logically? Severus would spend this last year in the past, he would gain the opportunity to better understand himself and Hermione, he might be able to prevent the tragedy, and he would come back to us at the end. We would win!"

"Such an optimistic Gryffindor you are!" Poppy snorted. "It seems to me, you don't know our Severus at all. Everything was always too difficult when it concerned him and Hermione. Severus almost died from Nagini's bite, we barely managed to save his life, he spent an exceedingly long time recovering, and after all that, he reluctantly agreed to return to Hogwarts. Then he met Hermione after she had come to Hogwarts to become Remus' Apprentice, and she and Severus had been fighting ever since. Later that year, she lost Ron, the Ministry issued this damned Marriage Law, and Severus had no choice but to offer Hermione his help. And you are proposing to immerse him in that crazy year one more time! This is inhuman!" Poppy huffed annoyingly.

"Ma chèrie, it would be inhuman to leave everything as it is. To watch Severus slowly sink into depression, having lost the meaning of life… Optimism or not, but sometimes you need to have the courage to take the first step. Besides, Poppy, Severus still does not know many facts from his own past. Who knows, maybe if he had known everything, he would have understood his wife earlier and far better."

"Oh, yes, especially if he knew that Hermione demanded the Unbreakable Vow from you when we saved Severus' life that terrible night in the Shrieking Shack," Poppy grumbled, still disapproving of the Gryffindor plans and strategies.

"Of course, or how you stopped Severus' soul from tarnishing itself with Avada's curse and secretly killed Albus yourself, didn't you, Poppy?" Minerva arched an eyebrow. "And you dare to blame my House for our mindless courage."

"Healers have the inviolable right to use all three Unforgivable without harming themselves," Poppy lifted her chin. "Plus, Albus wouldn't have survived that year anyway, so we could say that our plans quite successfully intervened in his sophisticated scheme of planning revolutions from scratch. We saved Severus's life."

"Let me correct you, Poppy, it was Hermione who saved his life," Minerva said meticulously, recalling that terrible day.

Heavy grey clouds were forming over Hogwarts. A disgusting fine rain was like a thick mist in the air, the smell of dampness hung like a premonition of an upcoming disaster. The Shack smelled of mold, blood, and despair. Somewhere in the distance, the sounds of battle raged, the cries of the fighters rang out, and the groans of the wounded echoed. The girl, dressed in ripped, frayed jeans and a baggy stretched sweater, did not hear the battle as she made her way towards the Shack. She was determined to change the course of history and even if she failed to save the world, she still could still save at least one life. Suppressing her bursting sobs of panic, she drew a silvery arc in the air and the Otter Patronus rushed off in search of the Head of Gryffindor.

He was not breathing. The girl fell in shock, kneeling in front of the wounded professor. Through the pounding of blood in her eardrums, she caught the slightest vibrations of air, barely audible cat footsteps, and a hardly perceptible breath. A lacerated wound on her professor's neck pulled the girl's attention, her brain feverishly attempted to pull forward any of the healing spells in her arsenal.

"Miss Granger…" the professor wheezed, gathering his strength.

"Hush, sir, you are not allowed to talk," Hermione whispered strictly and, opening her beaded bag, buried her nose inside. He couldn't just die here, there must be some remedy! At least something! Hermione's inner voice screamed. Professor Snape did not hear her desperate thoughts, instead, he reached for her hand and squeezed it with all his power, as if trying to say something. Surely he was going to say another highly moral nonsense about the Great Battle going right behind them, or about saving heroes and leaving criminals to die. Hermione had many sarcastic opinions on this matter, but she had nor the time, nor the wish to share her views with Snape who was barely clinging to life.

McGonagall, having already transformed out from her animagus form, quietly appeared behind and put her hand on Hermione's hunched back.

"Vulnera Sanentur, girl, I think Severus is trying to tell you exactly these words. Are you familiar with the spell?"

Having noted the understanding in Hermione's eyes, Snape squeezed out an uneven breath, almost choking on his own blood before passing out with a sense of accomplishment. Hermione grabbed the wand and began to weave a complex healing charm, hoping she would have enough power to perform. Minerva McGonagall unceremoniously opened her best student's bag and purposefully began to look for something.

"I assume our plan is still valid?" Minerva asked, waiting for Miss Granger to be silent for a moment, catching her breath for a new series of spells.

"The potion of Life-giving blood is in my jeans pocket, if you're ready, then I'm ready," Hermione replied.

Minerva shook her head at such recklessness: simply unbelievable, it was the most valuable potion, brewed from the rarest ingredients that she and Poppy managed to get by hook or by crook, and this girl kept it in her jeans pocket! Thank Merlin, Severus had passed out and didn't hear all this nonsense!

A draught of Life-giving blood, or Animam Sanguinis, was the potion which recipe Poppy was able to find in a treatise on the dark arts by a seventeenth-century Provence magician who narrowly escaped the fire of the Inquisition. According to eyewitnesses, the sorcerer lived in a stone castle on the outskirts of the forest and, in the best traditions of Gothic novels, instilled fear in all residents of the surrounding settlements. Rare daredevils dared to ask the wizard for help when things were going badly, but it was said that he never refused anyone. The sorcerer had a daughter, a talented sorceress who followed in her father's footsteps and brewed potions for the royal court. Admirers wooed her from all sides of the country, but the proud woman preferred solitude and her herbs. Once the rejected gentleman, a very capable magician, decided to take revenge and poisoned the sorcerer's daughter with his own poison, which had no equal.

The sorcerer spent days and nights brewing the antidote, having tried all the combinations of herbs and healing charms he knew, until one day he decided to take a risky step - he mixed sapphire powder, ginseng root, young mandrake embryos, grape bark, liquid gold, and his own blood.

The blood of any creature at all times was considered a sacred substance that bore magic and gave life, transfusing blood meant taking away magic, but the sorcerer was on the verge of despair. Having healed his daughter with the potion, he gave her, in the same way, a part of his life force, and his spell saved her life.

Hermione ignored the prejudices of the sorcerers both ancient and modern, giving the potion drop by drop to Severus, and resolutely placed her wand to the Dark Mark pulsing on his wrist.

"Hermione, this is too dangerous! I can't risk you like that!"

"Professor McGonagall, I won't change my mind about this plan, and truthfully, I would rather send him to St. Mungos, but we have no time, and you will be much more useful on the battlefield than I am, so, please, either help me or leave."

"My darling, your magic is drawing the power for the spell from your own aura, if it drains your magical reserve, you both will die!"

"So, help us, Professor, this is our last chance."

McGonagall didn't dare to object anymore, placing her palm on Hermione's back and sharing her own power with them. Hermione took Severus's hand and, concentrating, chanted the words in old French. Drop by drop, syllable by syllable, her aura glowed with golden light, enveloping them in a shimmering dome of pure light. Slowly, as if seconds stretched out into eternity, Severus began to come to his senses, the wound on his neck healed, bruises and cuts smoothed out, his pulse began to beat, the Dark Mark turned pale. McGonagall shook Hermione by the shoulder.

"Enough, my girl, the magic of the Mark is too dark to try to get rid of it right now. You need to rest, then I'll call Poppy, and we can handle it ourselves."

Shaking with exhaustion, Hermione struggled to her feet and demanded eagerly from Minerva:

"Professor, you must make me an Unbreakable Vow that you will never, under any circumstances, tell Professor Snape that I saved his life! I don't want him to owe someone a Life debt. He earned his right to be free, and I... Please, Professor McGonagall, take the Vow!"

Poppy Pomfrey, who arrived just at the moment to hear this conversation, had no choice but to witness the oath.

Severus stared thoughtfully at Lupin, who stood at attention in front of him, like a student before the headmaster. An incomprehensible rage and a fit of jealousy splashed in Severus' soul, but Remus did not notice the confusion of his interlocutor.

"Here, Severus, I was sorting through old papers, and found Hermione's diary, so I thought it might be useful for you."

With that, Lupin handed Snape a thick notepad with a holly print on the cover, not noticing how Severus turned pale when he looked at the picture.

"Do you remember how she was always writing something, or constantly drawing some kind of charts and pinning her hair with her wand, an unimaginable recklessness, in my opinion," Lupin said with sadness in his voice and, without waiting for a response, left the laboratory.

Snape carefully, as if afraid to break the fragility of the moment, flipped through the pages, gazing at the characteristic curve of the letter "a", at the sharp "k", at the ridiculous markings in the margins, at the ornate curls of new spells, and suddenly froze as if thunderstruck, almost dropping the diary.

But, of course! Hermione's stupid habit of stirring potions with her wand instead of the string rod! She constantly ignored his comments and never used a stirrer! The vinewood of her wand, coming into contact with the vapors of the potion, always sparked, adding new elements to the elixirs and tinctures.

The vinewood was considered a symbol of immortality and eternity. And it seemed to be exactly the final ingredient that Severus lacked for his Potion of Pristine Memories.

"Oh, how clever you are, my dear heart! You can't even imagine how clever you are!" Snape whispered to the diary and stroked the holly on the cover with his fingertips.