Sev made his way rapidly downstairs to the bottom of the tower. Once he was there, he found a dark corner and stood watching the foot of the Whomping Willow with a certain amount of curiosity. If what he'd just suspected was actually true, then the passage under that tree was not the safest place to be right now...
In about thirty seconds' time, the two boys came barrelling out as if their robes were on fire. Sirius yanked the cloak out after them before the passageway could close on it, and they both collapsed together; out of breath, but laughing. They'd probably come a hairsbreadth away from their deaths, but neither of them seemed to care. Sev didn't suppose either of them really believed that they weren't actually invincible.
Not even James and Sirius, though, were quite crazy enough to be visiting and then running from a werewolf just for the fun of it - especially when it was one of their closest friends in human form. They had to be trying to do something, trying to test something... Sev realised they must be trying to find some charm or enchantment that would allow them to visit their friend in wolf form without being attacked.
Clearly, they hadn't found it yet. If they'd known since the first year, they'd probably been doing this every month; searching and searching for something to try, then ducking down the tunnel and risking death to find out if it worked.
This, Sev was fairly sure, was because neither of them were creatures of logic.
Much of the next morning he spent researching methods of suppressing and controlling lycanthropy. Not, of course, that he would endanger his position by passing such information to James and Sirius - but it was knowledge that had suddenly gone from trivia to something relevant; and Sev always liked to have the relevant data at his fingertips.
The books all spoke of how it couldn't be done, but Sev knew how to read between the lines. He duly noted comments about how werewolves were less enraged by the company of animals than men, and various discussions of spells that seemed effective in warding them off.
There were also rumours of a Wolfsbane potion that would quiet a werewolf and render it harmless during the full moon - but if the recipe had ever existed, it had been lost in the mists of time.
Sev had no way to recover that recipe - but he had a true flair for potions and a brain that could recall every tiny clue that had been fed into it. He strongly suspected that a few successive attempts would allow him to make a useable Wolfsbane... but there would be no safe chance to test it, so he merely squirreled the idea away in his head in case he should need it in later years.
However, whilst he was browsing the potions section of Professor Malachite's private library, he found an interesting little recipe in the back of Dark Elixirs... Trustasiem.
A variant on the powerful Veritaseum truth potion, Trustasiem had the interesting little quirk of making a its drinker feel extremely trusting... spilling their innermost secrets not because they were compelled to, but because they believed themselves safe in doing so.
An even nastier little side-effect was that the victim, if not put under too much pressure, would not recall the questioning session at all. Though their original feelings for the person concerned would return, the time for which they had been under the influence would be forever cloaked in trust for them - the victim would be literally unable to contemplate the idea that they could have been used in any way.
No wonder this potion was found in a book of the Dark Arts. It was a deeply nasty and violating little mixture... and Sev could think of a good use to put it to.
Guilt was not a completely alien concept to Severus Snape, but his logical brain would not allow him to apply it to himself in any situation where it wasn't justified. There was nobility, and there was pragmatism; and nobility was for the James Potters of this world, not the Severus Snapes.
The delicate nature of the relationship he was building with Lucius Malfoy made it far too dangerous to use the potion on him. Besides, Sev was sure Malfoy didn't know half as much as he thought he did; his partnership of sorts with the other boy was not a short-term venture. He would have to follow Malfoy all the way up the Death Eater ladder to learn the innermost secrets.
However, such a potion would be ideal for quickly questioning one suspicious individual; Professor Cuero. Two or three drops, a similar number of questions, and it would be done.
Perhaps, in a way, Sev's cold and calculating nature made such a venture a less bad thing for him to attempt than for another. Another, no matter how 'noble', might be tempted to pry too deeply into someone else's personal secrets, but Sev would ask the relevant questions and inquire no further.
The biggest difficulty was going to be slipping Cuero the potion without his knowledge. Hogwarts students were not renowned for thoughtfully bringing their teachers food and drink, least of all a cold, distant boy like Severus Snape.
It would be easy enough to slip the potion in with some misdirection at dinner - but that was the last thing he wanted. This had to be done in complete privacy, if it was to be done at all.
When Sev had still owned the invisibility cloak, he had used it to explore every corner of Hogwarts - not just the innermost sanctums. That was what made him different from the run of the mill ambitious Slytherins; all of them would think to study Dumbledore and Malachite, but very few would bother to track the movements of the caretaker and groundskeeper.
Sev happened to know that Hagrid, the half-giant groundskeeper, was extremely fond of animals; apparently, the fiercer, the better. He also loved to make sweets, albeit rather badly.
That, in Sev's mind, added up to Professor Cuero having stacks of Hagrid-made goodies thrust upon him as the groundskeeper took any excuse to drop in on him and check out the latest dangerous beasts. Cuero, if he had any sense, would approach them with caution, but often Hagrid's penchant for huge volumes of sugar encouraged people to risk broken teeth and try their luck.
Sev was an accomplished opener of locks, both magical and non. He had spent a great deal of time last year studying the mechanics and practicalities of getting through doors and windows undetected. An invisibility cloak was only as good as the wearer's ability to pass unnoticed.
He tailed Cuero several more nights; never catching him up to anything suspicious, but closely following his routine. When he had a good idea of exactly when was safe, he silently let himself into the Professor's hut.
Unlike most of the Hogwarts staff, Cuero lived in a hut in the grounds like Hagrid. He claimed to prefer to be close to the animals, although most people agreed it was more that he didn't like to be near other people.
The first time Sev broke in, he did nothing and touched nothing. He carefully studied the positions of everything, checked out all potential hiding places, and tested all the exits. Then he waited patiently.
Three days later, his observations were rewarded. Hagrid dropped in on the Professor, who bore his presence with a kind of long-suffering resignation. When he departed, he left behind an enormous plate of various sweets. Cuero regarded it with a distinctly wary expression, and then hurried out of the hut to do his usual rounds of the magical animals.
Sev found that telling. If Cuero hadn't intended to eat the sweets at some stage, he would have either taken them out to surreptitiously feed to the animals, or - if he worried about what that might do to their health - simply disposed of them. The fact that he had left them behind strongly hinted that his sweet tooth outweighed his sense of self-preservation.
Armed with the tiny vial of Trustasiem he had secretly made up, Sev quietly slipped in and added a few drops to the tray of sweets. Like the Veritaseum it was derived from, Trustasiem was colourless, odourless, and tasteless. Once Cuero had taken a few drops of the potion in, the effect would be instant and last for nearly an hour.
Sev secreted himself in a dark space behind a wardrobe, and cast a little spell that had come in useful during his first year. It wasn't as foolproof as an invisibility cloak, but it made him... shadowy. Professor Cuero wouldn't see him unless he came and peered into that corner with the express purpose of checking for someone hiding there.
He knew how long it usually took Cuero to make his rounds, but remained unflustered when he was late back. A less experienced spy might either worry that he was missing something or panic about being discovered, and try to leave. Sev knew that doing that was just about the best guarantee of getting caught you could give yourself.
He waited patiently, and surely enough, a few minutes later Cuero returned. He sat down and picked up a book, but didn't even look at the tray of sweets. Sev was untroubled, prepared to wait as long as it took.
It took nearly half an hour. Cuero kept glancing over at the tray, grimacing, and looking away again. Sev suspected he had a raging sweet tooth, but had met Hagrid's attempts at cooking before.
Finally, greed won out. The teacher moved over to the tray of sweets, stared down at them for a moment, and reached for something misshapen and oozing honey. He pulled a face at it, and then gingerly popped it into his mouth. Apparently having got lucky and not broken any teeth, he returned to his books. Sev waited a few moments, and then emerged from his hiding place.
Professor Cuero looked up at the sound, but he neither jumped nor looked angry. "Oh, hello there, Severus," he said pleasantly. "Were you waiting for me?" The harsh lines to his face and grating edge to his voice had both smoothed out, and he suddenly seemed much younger.
Sev casually made his way over to the seat opposite him, and sat down. With Cuero under the effects of Trustasiem, he could have snapped off his questions interrogation-style and the teacher wouldn't think it odd - but blatantly relying on the infallibility of his magic had never been Sev's style. An irony, perhaps, because the nature that made him so cautious also made his magic more reliable than anybody else's.
"Professor," he said, similarly pleasantly. Any Gryffindor who dropped in to see the two of them 'chatting' so nicely would probably drop dead of shock. "I was hoping you could answer a few questions for me?"
"Of course, of course," agreed Cuero airily. It took a moment for Sev to realise who his brand-new open manner reminded him of: Professor Dumbledore. It was that same unblinking faith that those around him could be trusted - in Sev's opinion, the one flaw in the headmaster's powers of observation. He had every bit of the intelligence and observation skills Severus owned - but they weren't tempered with that cynical 'assume nothing' attitude that made a perfect spy.
He kept his tone as light as if he had called in to check the details of a homework assignment. "I was wondering if you could tell me about the skull symbol we saw in the sky last week?"
"Ah, yes. The Dark Mark." Cuero frowned. "Nasty business. Symbol of the Death Eaters, you know."
From those short sentences, Sev had already derived much of what he needed to know. Cuero was aware of the Death Eaters, didn't belong to them, and didn't agree with their mindset. Which made the attitude he displayed in classes... interesting.
"You know a lot about the Death Eaters?" he asked with a tone of innocent curiosity.
"Ah, yes, I'm an expert, you know. I was with the team that investigated their actions in the Harrowgate case."
'With the team' - that meant he was part of the Ministry of Magic; probably an Auror. Which meant Malfoy's casual assumptions of his loyalties were deeply misguided.
"So you're here on a covert mission then?"
"Oh, yes. Very hush-hush." Cuero tapped the side of his nose. "I can rely on you, I know, but there are a lot of students here..."
"Malfoy and his friends?"
"Hmm, yes. Thirteen years old, and already well on their way to being corrupt. Get them young, and you'll have them for life. Oh, he's a cunning one, this Voldemort."
"Voldemort?" It was a name Sev had never heard before - the 'mort' on the end, meaning death, made him sure that it wasn't any traditional wizarding name, and it certainly wasn't anything from the Muggle world. "Who's he?"
Cuero pulled a face. "Well, nobody knows, do they? A couple of the Death Eaters we've observed have mentioned him, and we think he's their leader, but other than the fact that he's in Europe somewhere, we know nothing. Hard, very hard, to get decent spies in their camp. A problem they apparently don't have," he added, a trifle bitterly.
"There are spies here?"
"Just the one, we think, but it's anyone's guess who. Those morons in the Ministry are convinced it's young Hagrid - but the man's a gentle giant, and hardly a schemer. Obviously it isn't Dumbledore... but anyone else is fair game. You saw yourself how they slipped Fennel in, and he was hardly subtle, was he? This other one's a far more slippery character."
"You think this is the person who killed Professor Cephus?"
Cuero scowled. "Sure of it. But they're clever - far too clever to reveal themselves too easily."
"So you're trying to convince them you're one of theirs?"
"Yes." He grinned slightly. "Picking on the Gryffindors was a Slytherin tradition back when I was at school; that never changes. Paint yourself as a true Slytherin, and they're half the way to believing you're evil."
Sev nodded, getting up. He had all the answers he needed, and hanging around for more was asking for trouble.
"What they don't seem to realise," Cuero reflected half to himself, "is that while half of us might grow up to be dark wizards, the other half grow up to be the best damn Aurors in the business. I mean, look at you. You're one of ours, aren't you?"
Sev paused on the way to the door, and permitted himself to smile wryly at it. Despite the fact that he had forced Cuero to believe that through magical trickery, it was really nothing shy of the truth.
"Yes; I'm one of yours."
He slipped out of the door, and left Cuero to recover his senses and lose his memory.
