Thanks to all of you who took the time to follow, favourite and review this story.

AN 2020/12/11: chapter betaed by the amazing Miette and dpstone12 :) A few scenes developped for better coherence with the rest of the story but no plot change.

Severus grimaced as the memory began unfolding. It had been the day he had known with certainty that Dumbledore was not as good as everyone made him out to be.

Severus was hurrying from the arithmancy classroom. He had remained after class to ask some questions on how the day you collected one ingredient would influence a potion and if it could be enough to change the effects of the potion in major ways. Professor Vector had been delighted by his interest in a branch not explored by many. She had given him a list of books on the subject, even writing him a pass to the restricted section of the library. But now he was late for lunch and did not want to chance on the Marauders.

"Hoy Snivellus!"

He froze, seeing Potter appear in front of him. He furtively looked around, his stomach dropping when he spotted Black and Pettigrew behind him, and Lupin farther away obviously mounting the guard.

"So Snivellus, playing the teacher's pet to cover for your Dark practices?" drawled Potter. "You know Sirius has a lot of experience from his family recognizing Dark Wizards, and you stood out from the start."

"Dark magic is baaaad," singsang Black. "Bad little snake. I am sure your Lord Voldemort likes that. You know my family is behind him... It's the only proof I need to know he is a Dark Wizard. And so are you because you wanted him as Minister of Magic!"

"Oh yes," snickered Pettigrew. "Snivellus should be taught not to use Dark spells, especially against us!"

"Indeed," agreed Potter. "What would the Headmaster say?"

He paused then smirked. "What would beautiful Lily Evans say?"

Severus struggled to keep his head. The mention of Lily by pretentious Potter always made him lose his temper, it impaired his judgment and he made tactical errors.

This had not changed, thought Severus bitterly. Potter had been the instrument of the end of his friendship with Lily. He had no doubt the Marauder would do everything to keep her away from him. Potter seemed to have set his sights on Lily since their first ride to Hogwarts. Would they still be friends if the git had not attended Hogwarts with them? Or was Black the one who had pushed Potter to target Severus? Why couldn't their friendship endure despite those two idiots' efforts?

He grimaced as he focused his attention back on his memory.

"Soooooo," said Black, "Where should we begin?"

Severus had just the time to cast a non-verbal Protego, making Black's Jellylegs charm rebound against a wall. He had reached the fifth year's Defence Against the Dark Arts program at the end of summer and discovered the possibility of casting spells without saying them. He had immediately recognized the edge it would give him in his war against the Marauders and had practised as much as he was able to since the beginning of the year. Another bonus was that it would be harder to detect if he cast Dark spells and Lily would stop hounding him about stopping his study of the Dark Arts.

Not losing anytime, he fired a Bat-Bogey Hex toward Black and Pettigrew then a Tooth-Growing Spell on Potter while rolling toward him. Cries of pain told him his bats had found their target but he did not lose his concentration as Potter evaded his spell in a practised Quidditch move. Potter cast a sticking charm on him that found his left foot, limiting Severus movements.

The Marauders now circled him and fired diverse spells and charms on him, while Severus struggled to maintain his protective shield all around him.

Severus had noticed during classes that the power in his spells was not as great as some of his peers. Indeed, his control of the spells was always perfect but he did not manage as much intensity as Lily or Evan. He knew the Marauders also overpowered him, with the exception of Pettigrew. At first, he had only been concerned about his grades as the lack of power decreased them slightly but as months passed, he had realized it could impact his capacity to defend himself.

Fifth year Severus shook his head to himself. More than once, he had regretted that Mother had not bought his wand at Ollivanders. He still wondered if one day, he would be able to use his wand's whole potential. He would pass his OWLs practicals, but the price had been high. This fight had only been the beginning of his troubles with his wand.

Severus felt his shield shake as he desperately racked his brain to find a way out. Finally, he found a risky solution as he had to fire two spells that he had never tried non-verbally consecutively and quickly, but he could not let his three assailants know his intentions for it to work.

He took a deep breath, focusing on the two spells and the results he wanted. He waited for a time when all three cast a spell together then, careful to control his spell intensity, cast Ascendio. He rose in the air surprising his three opponents as most did not care to learn to use this spell to fly, finding it useless when brooms existed. Severus was not able to do more than remain up in the air yet, but it was enough right now. While focusing on remaining in the air, he cast Deprimo, making his wand movement large enough to cover his three targets. The three Marauders fell on their knees under the pressure of the spell that was forcing them down, and struggled not to completely lie on the floor. Severus went back on the floor, surveying the now powerless Marauders who had lost grip of their wands under the pressure.

He was carefully escaping to the great hall when someone taller than him blocked his path.

The colourful dresses made Severus groan inside. The Headmaster was here, taking in the scene. Severus noticed Lupin just behind, trying to disappear inside a wall.

"Well Mr. Snape, if you would be so kind and lift the spell from your comrades," said Dumbledore genially, also a brief look into his eyes told Severus the Headmaster was not happy.

Of course he was not, thought Severus with a flicker of satisfaction as he watched the memory-Dumbledore. One lone slimy Slytherin had bested his golden boys. It must have stung the older man's pride.

He reluctantly released them, keeping an eye on their movements.

The three Marauders made a show of standing back up with difficulty, recovered their wands then stood expectantly in front of the Headmaster, on the opposite side of Severus.

"May I ask what happened here?" asked Dumbledore in a deceptively mild tone.

"Headmaster," began Potter, "we were going to the great hall when we crossed Snape. We exchanged a few words about Lord Voldemort and I think he didn't take it well because suddenly there was pressure and we could not remain standing. Then you arrived to save us," he ended with a big winning smile toward the Headmaster.

Dumbledore watched him a few moments before turning to Severus.

"Do you agree with this version Mr. Snape?"

Severus struggled not to explode at Potter's blatant lies and tried to speak in a normal voice.

"I remained behind after class to talk to Professor Vector. I was hurrying to go to lunch when they blocked me. They attacked me relentlessly. I protected myself with a shield but I was getting tired. I tried this spell as a last resort and it worked. I was leaving for lunch when you arrived."

"Hmm... You should know, Mr. Snape, that Deprimo can cause serious damages on the human body if you put too much power into it."

He paused, looking him in the eyes. Severus clenched his fists. Once again, he was the accused when he had only been defending himself.

Suddenly, he felt a weird sensation in his head, a pressure that went on intensifying every second. He saw himself in the air casting the spell on the Marauders and caught a glance of another figure before the pressure was so painful he fought against it.

At once, the pressure vanished and he was looking at the Headmaster who was frowning slightly.

"Very well, I suppose we are lucky you are not very powerful Mr. Snape," said Dumbledore.

Severus reddened and heard the Marauders snicker.

"Do be aware this spell borders with the Dark Arts."

Severus sneered when he saw Black stuck out his chest at hearing the proof the Slytherin was a dark wizard. It did not matter that the spell was not on the Dark spells list of the Ministry. This list grew on every year. One day, only Lumos would be left to cast safely.

This was another reason why Lord Voldemort needed to become the next Ministry of Magic, reflected Severus as he watched the memory. Soon, Minister Birkins would only allow the blandest uses of Magic.

"Mr. Snape, it will be 20 points from Slytherin and two detentions with Mrs. McGonagall."

Severus sighed, defeated. Of course, detention with the stern professor for fighting with her lions.

"Misters Black, Potter and Pettigrew, it will be one detention with professor Slughorn."

Severus refrained a cry of injustice. Black and Potter were both in the Slughorn club, no doubt the detention would be light. Even if Slughorn now recognized Severus' talent in Potions, he was nowhere near the professor's favourites. Those were Potter and Lily.

"Now gentlemen, hurry to lunch before it ends, and no duelling please," said Dumbledore sternly.

The Marauders went quickly while Severus took his time, thinking about the pressure in his head and the pictures he had seen in these moments. The more he thought about it, the more he was convinced it was Dumbledore he had seen in his mind. Why would he see the Headmaster in association with a memory he had not been part of? And why would he feel a pressure while remembering a memory?

Severus arrived at the slytherin table and quickly filled his plate. Then he took a piece of parchment and a pen, and got to the task of understanding this mystery.

At the end of his lunch, he had come up with a theory:

What: Pressure in the head + Memory of casting Deprimo + Pain
 Memory vanished with the pain and pressure
 Maybe figure of Dumbledore in the memory when he should not be there

When: While talking with Dumbledore about the above memory

Who: Dumbledore + me
 Did not see the Marauders cast any spell

How: Health problem unlikely
 Result of a spell more probable
 A spell exists to read minds?!

Why: To check my version of the events?
 Why only saw the end of the memory and not the Marauders' attacks?
 Why not check Potter's too? did not noticed any discomfort on Potter's face during his false account of the story

Need to go to the library

For once, Severus was in luck. He only had history classes with the ghost professor Binns and Potions with Slughorn. Being so advanced in Potions and learning History from the book Mother had bought him in first year, he decided to skip classes for once and go to the library instead. There, he consulted the books register that Madam Pince let him check unsupervised, a rare privilege. She was used to seeing him almost every day studying quietly and she knew he was always careful with her books. Since third year, she had given him access to the register which made it much easier to research a book than researching by shelves, especially when you were not sure of what you were looking for.

He quickly found several books on the magic of the minds. Riffling through them, he found out the art of reading minds was called Legilimency, and the art of defending against it Occlumency. Sadly, the books were not very informative, except to say those were difficult to learn and master. There was no clue on how it worked or how to learn it. They remained vague, saying Legilimency was considered invasive magic. There was even less information on Occlumency.

Frustrated, Severus remembered he had a pass to the restricted section from Professor Vector and immediately made use of it. There, after almost an hour, he found a treasure: Occlumency, theory and practice.

Severus was excited but he knew he could not check the book out without arousing suspicions. He noted its references then impatiently waited for the next Hogsmead weekend to buy it. This felt too important to ignore, even if it meant Severus would send less money to Mother this month.

A few weeks later, he began studying Occlumency from this book amongst others. This one was apparently the most complete to understand and learn Occlumency but the others were necessary to understand the basis and added useful information on the link between Legilimency and Occlumency.

Occlumency is commonly defined as the art of protecting one's mind. However, this definition only covers a part of the subject. It is more exact to say Occlumency is the art of mastering one's mind. When one masters Occlumency, he will notice an improvement of his memorizing capacities a well as of his deducing abilities. He will have better control of his feelings, meaning his tendencies to act on impulse will diminish. He will also be able to protect his mind from Legilimens, as well as from most nightmares. All this stems from the control of a Master Occlumens over his mind and memories.

There are three main steps in learning Occlumency:

1: Finding your safe place
Two ways of finding your safe place are currently known.
For the first way, you must focus on a feeling of safety, clearing your mind of any other thoughts. When you manage it, a picture of your safe-place should naturally come to your mind. It can come two ways: either one place comes to the front and remains, or several places come successfully with one appearing several times. This one is your safe place, the one strongest attached to you feeling safe. It can take several months to find your safe-place this way, depending on your natural aptitude for Occlumency as well as on your past experiences. Most learners will in fact have a choice between two or three possible safe-places that their subconscious will propose. In this case, they must choose the one they consciously consider as safer.
The other way is usually quicker but more painful and riskier for the learner. You must try to focus on nothing while a legilimens enters your mind brutally enough to make your mind react and protect itself but not strongly enough to damage your mind.
The legilimens must repeat the attack several times consecutively for about 10 minutes, once a day and during two weeks at most. By then a picture should be present at the forefront of the learner's mind when he thinks of protecting his mind. This is his safe place. The safe-place is fundamental and you must not proceed to step 2 without being certain of it.

2: Shaping your mind into your safe place
For now, your mind only assumes the form of your safe-place when you consciously think of safety. You must train it to remain into this shape all the time until it remains this way even when you do not think about it.

3: Controlling your safe place
Once your mind is shaped, you need to learn to control it. First, you must be able to move into it at will. Then you will try to transform elements from it and to add elements to it at will. Those are the keys in Occlumency, you must be able to add what you need to your safe-place at will, without deforming it.
When you have mastered these three steps, you should be able to delve into the more complex branches of Occlumency. Do not attempt anything before mastering the three steps above.
It should be noted Occlumency is a difficult subject that has seldom been mastered and that is successfully practised by few. Most Masters Occlumens were natural Occlumens. The surest way to know if you are a natural Occlumens is to have a legilimens try and enter your mind. If you feel the intrusion, you are most likely a natural Occlumens and should be able to succeed in your study of Occlumency. Most Occlumens can learn Legilimency too. For more information on Legilimens, see Legilimency, theory and practice.

The older Severus smiled. The fact he had felt Dumbledore in his mind meant he was a natural Occlumens and had given him even more drive to learn. He had read and practised every evening, cutting in on his advanced study time, but it had been worth it to thwart Dumbledore later, he thought darkly.

He had told Lily about the incident with Dumbledore but she had not believed the Headmaster would breach the privacy of a student in this manner. He had been miffed by her disbelief and decided not to tell her about Occlumency and his learning of it.

Severus sighed. His observation of Lupin had finally born his fruits around spring and he had become convinced the Marauder was a Werewolf. It explained the monthly sickness as well as his disappearances for two or three days. Indeed, Werewolves transformed the three nights of the full moon and the transformation was painful. It left the subject weak and hurting in his bones the day after. Severus had also noticed the closer the full moon got, the more Lupin got emotional. The usually nice and cowardly guy almost grew teeth the days before his transformation.

Fifth year Severus shivered. Werewolf's teeth were no laughing matter as he had discovered earlier in the year.

He had told Lily about his suspicion a little after she had refused to believe his accusation of Dumbledore. She had laughed and then gotten angry when he insisted. She had told him there was no way gentle and well-mannered Remus was a monster and she had accused him of wanting her to give up on her Gryffindor friends to have her for himself. Severus had been hurt because yes, he had begun watching Lupin out of jealousy but now he was friends with Lily again, he had wanted to warn her about the possible danger. She had even accused him of wanting to isolate her to make her want to support Lord Voldemort.

Fifth year Severus sighed again. Those had been her friends' words. The more they advanced into the year, the greater their peers' pressure had been to end their friendship.

Her friends had denigrated his looks, his poor clothes and his nasty temper while his own friends had told him again and again she would let him down when she grew weary of her crusade and joined the general Gryffindor opinion of Slytherin.

In reaction to Gryffindors' taunting, Slytherins had begun using the word Mudblood regularly instead of Muggleborns. Jonathan had told him his family was using it a lot during summer and he had taken the habits with the Muggleborns he disliked. It had not helped Severus' case with Lily even if he himself did not use the word, and Evan and Jonathan were civil to Lily. Still, after he had told her about Lupin, she had distanced herself from him again, though she had kept on defending him against the Marauders and any Slytherin haters.

Meanwhile, the rivalry between the two Houses had increased every day. Pranks now were harmful and Mrs. Pomfrey had to heal at least one Gryffindor or Slytherin a day. Slytherin were losing points quicker than Gryffindor, mainly because during fights, they used borderline Dark spells that were frowned upon by the teachers, no matter that the light spells from the Gryffindors did as much damage. Moreover, it seemed to Severus that when caught, teachers believed the Gryffindors more than the Slytherins.

He sneered, thinking about Dumbledore favouritism that had showed more every day.

Rumours began about Slytherin being an all Purebloods house bent on conquering Mudbloods. That was false but as often happened with rumours, all Hogwarts was soon convinced of the fact. In truth, there were Muggleborns in Slytherin – and one Half-blood - but thanks to rule three, they had blended in by the Christmas of their first year. Those that did not were few and protected by rule four until their fourth year. Then, the house politics made sure they were miserable. Severus was only aware of two during his years at Hogwarts and both had transferred to Beauxbatons a few weeks after the beginning of their fourth year. He heard rumours one had left after being severely injured but he never got confirmation.

One could have thought Slytherin's Muggleborns would be ostracized after Severus' third year events. They would have been very wrong. All of them had been hurt by the muggle world and were the living proof that Lord Voldemort was needed. Severus did not think they were Slytherins by chance. The sorting hat had belonged to Gryffindor but been spelled by all the founders. Salazar had wanted them protected, as did Lord Voldemort's faction.

Thus, during the summer after Lord Voldemort failed election, several Slytherin Purebloods led by Lord Abraxas Malfoy had decided to put into place an unofficial sponsorship for Slytherin's Muggleborns and Half-bloods. According to Jonathan, many muttered they had waited far too long to implement it, waiting for a hypothetical agreement from the Ministry.

As per Slytherin fourth rule, the sponsorship would begin in their fourth year, if the student accepted the proposal of their sponsor. The younger years were considered wards of Slytherin and should come to any fourth year and above if help with their home situation was required.

Severus had been torn between disappointment at not being able to call for help as a younger year and relief that he did not have to choose whether to ask for help or not.

Severus nodded to himself. He had no idea how he would have reacted during the previous summers if he had been able to call for help against his father. How Mother would have reacted to other Wizards attacking her husband. Badly– he was sure. She had loved him still.

He pushed the thought aside. At least, he had been lucky to be among the first mentorees.