Severus Snape was annoyed. He was annoyed that his students were so flippant about his subject, which was nothing new, despite it being a new subject. He was quite annoyed that his old head of house had returned, and kept criticising his style. He was definitely annoyed that half of the students in one of his years were so far behind the others, which was new only in that it somehow seemed to be primarily Gryffindors who were ahead. He was especially annoyed that it was his Slytherins in that year who seemed to be the most behind.  

Most annoying of all was that he had so far been unable to get the smell of cloying lavender out of the Defence Against the Dark Arts office, and somewhere, something -  he had as of yet been able to identify what exactly- kept meowing.

After the first three weeks of classes with his new NEWT level class, Professor Snape realised that he was going to have to find out exactly who had covered what information. This was initiated by the fact that Neville Longbottom, of all people, had managed to cast an almost perfect Blasting Hex on the practice dummy at the front of the room, and that was on his first attempt.

Snape watched with narrowed eyes as Longbottom made his way back to his seat, shyly accepting congratulations from Granger, Macmillan and Finnegan. Potter was staring out of the window. Again. At least Snape knew how to handle this.

“Mr Potter!” Snape barked, causing Potter to jump, and in the process, drawing a thick line of ink across his sheet of already indecipherable notes. “A critique of Mr Longbottom’s Hex, if you would be so kind?”

Potter’s eyes flickered nervously between Snape’s own, Longbottom, and the front of the room. The dummy was still shaking slightly

“His wand movement was good, Sir, as was his pronunciation. The spell was powered adequately, but could have done with more channelled power at the start of the movement. It veered of to the left, as well, Professor, but not so far as to miss the target.”

Snape tipped his head to one side, considering the Gryffindor. He could have sworn the boy hadn’t been paying attention when Longbottom had come up to demonstrate. But it had been a fair assessment of the spell.

Snape looked carefully at Potter, taking note of how the boy was gripping his quill so tightly in his hand, the left as well grasped in a tight fist. His gaze too steady, and his jaw too tightly clasped.

“As you say.” Snape nodded, he turned away from the class, ostensibly to steady the mannequin, but mainly to give Potter a moment in which to let his guard down. He folded his arms and turned around to face the class. He was right, Potters hands were looser.

“Do remind us of the pronunciation, Mr Potter.”

The hands tightened, and the quill bent dangerously. A fat drop of ink spilled onto the table, unheeded.

“Sorry, Sir?”

“The pronunciation, Potter.” Snape blinked benignly. “For the spell that Longbottom just showed us.”

“I-“ Potter faltered. Ah ha! “I’m not so sure of it myself, Sir.”

Snape advanced past the rows of delighted Slytherin students, never mind that only one of them had shown any knowledge of the spell.

“But you just informed the class that Mr Longbottom’s pronunciation was perfect.”

Granger was sat next to Potter, and she pulled a face. Not quite a wince, but close enough. Students around the room shifted uncomfortably, Snape ignored them.

Potter opened his mouth, then closed it just as quickly. When he opened it again, Snape was ready to interrupt.

“Very well, Potter, to save you from the clearly significant embarrassment of mispronouncing the incantation. What is the name of the hex?”

“Name, Sir?” Potter asked weakly.

“We have been discussing it for the last half hour after all.” Snape allowed his voice to drop to its quietest level.

“It – We- That is…” The boy’s eyes dropped to look at his own useless parchment, then slid to the board at the front – empty of diagrams, then finally to Granger’s notes on the desk beside his.

Snape put his hand down on the notes in question, blocking them from view.

“Detention, I think, Potter. Tonight. With Mr Filch.”

The boy grimaced. “Yes, Professor.”

The remainder of the lesson passed in relative normality. Snape only just remembered the earlier annoyances for the day, and called out to Ernest MacMillan to remain back after the others had gone. Potter fled as soon as the class had been dismissed, not even bothering to clean up the spilt ink from his desk. Snape banished it with a tap of his wand.

“Professor?” Macmillan sought his attention. Presumably the boy had another class to get to now.

“I have noticed a disparity in the knowledge base of half of this year’s NEWT students.” Snape started, as congenially as be could bear. “It is somewhat unexpectedly distributed. Is there a study group of which I am unaware?”

“No, Professor.” MacMillan frowned for a moment. “Not really, Sir.”

“Did Professor Umbridge, or perhaps Professor Moody teach the different houses separate curricula?”

“No, Sir. Professor Umbridge taught us all from the Slinkard book, and Professor Moody taught everyone the same as far as I’m aware.” MacMillan fiddled with his Hufflepuff tie for a moment.

“I shouldn’t really tell you about it, Sir. I’m a bit wary to be honest with you. You should speak to three Gryffindors about this, if you catch my drift, Sir.”

Snape did. His lip curled. It was heavily distasteful to have to seek out any of the Gryffindors. Let alone those three.

“Very well, you are dismissed, MacMillan.”

“Yes Sir.” The Hufflepuff hurried out of the room quickly, for some reason trying to catch his reflection in a cabinet window as he retreated.

Snape grimaced, teenagers were a strange breed.

Unfortunately, despite his best efforts to deny the need for speaking to Potter, Snape finally admitted he had to do so. There was a clear 8 point margin in the essays handed in between the Gryffindors and the Slytherins in their latest essays on classifications of shield charms. And certain others in the higher bracket as well – MacMillan, Finch-Fletchley, Corner. Children who had scored well on their OWLs, but average on their fourth year and below exams.

And Snape knew exactly where to find the boy.

He made his way down the Grand staircase, through the Entrance Hall, through the Great Hall and the Exploding Snap Club, to the Trophy Room, behind the Teacher’s Dais.

In there, as he had expected from an earlier conversation with Filch, was Potter. The boy had shed his robe and jumper, stood there in a definitely too-small school shirt, and huge, scruffy muggle jeans. His sleeves were rolled up out of the way and he was smeared all over with polish and Brasso, focussing intently on polishing an award for special services to the school.  Snape noticed with vindication that it had been awarded to the boy in question.

“Somewhat ironic.” Snape said, allowing the heavy door to close behind him.

Potter jumped gratifyingly, and glanced wide eyed at the Professor, his shock morphing into a more wary expression. He swept the rag in his hand over the plaque one last time, making a surprised noise as he read the inscription before shoving the thing unceremoniously back into the cabinet.

“Yes, Sir.”

Snape noticed absently that Tom Riddle’s award was no longer in the centre of the shelf – replaced instead by an old Quiddich Cup. The two of them stood staring at each other for a long moment.

“Do you know why I am here, Potter?” Snape asked, folding his arms.

Harry scratched his cheek with a grubby fingernail. “To assign more detentions?”

“Perhaps not if you responded with appropriate respect.” Snape said, pointedly.

Potter clenched his jaw at that, then visibly fought to respond, “Sorry, Sir.”  

“Better.”

Potter glanced over his shoulder, presumably at all the work he had left to do. Snape couldn’t care less.

“Do you know why?” The boy clearly did not. “My sixth year class has become somewhat of an enigma. I suspect you and your friends are the key to it, as you usually manage to be in the middle of every whisper of trouble going.”

“Are we, Sir?” Potter grimaced, “An enigma, I mean. Not in trouble…”

“What do you think of this?” Snape held out a sheet of parchment for the boy to take. Potter hurriedly deposited his cloth and polish on a nearby shelf, and wiped filthy hands on filthy trousers.

There was a table on the sheet, which the boy scanned quickly, glancing up at Snape as if to judge how much patience he had. Snape kept his face carefully blank.

The table showed the last 5 practical and essay assignments for this term, then the individual student scores by house – anonymised of course.

“Gryffindor is doing well, Sir.” Harry smiled. “Erm, Slytherin is not doing quite so well. Not badly, Professor, just kind of…”

“Below average?” Snape supplied, clearly not willing to have Harry say the same. “Any reason for this? Let me assure you, this is not reflected equally across the years. And somehow, I do not believe that Professor Umbridge arranged for a practical class on the blasting hex. Much less, one specifically for Gryffindors.”

Potter looked anxious, or rather, more so. Snape stared at him until he started to fidget.

“There was a few of us in a… study group. Last year.” Potter said to his own hands. “You remember when the minister came last year? When Professor Dumbledore…left.”

“You are referring to when Madame Umbridge convinced herself that the Headmaster was building an army of students to fight the Ministry, and caused him to turn fugitive?”

“Yes, Sir.”

“I recall.”

“Well that was us, Sir. Defence Association- the DA. Except of course we went and called it Dumbledore’s Army.” The boy closed his eyes, presumably having realised the stupidity of that name by now.

They stood in silence for another minute.

“You did not simply meet up to cheat on your Homework?” Snape said, almost hopefully.

“No, we practiced hexes, shields, jinxes.” Potter scratched his head. “The patronus for a while. Some theory of course.”

“Anything you did not cover?” Snape asked, a little snidely.

Harry nodded, seriously, “I had wanted to go into more depth with cursed creatures, inferus, werewolves, red caps. Cursed objects, of course. And we had covered the patronus, but not how to send messages with one, and hadn’t practiced with a Dementor- I couldn’t find a boggart. And some practice of spellwork in adverse conditions wouldn’t go amiss.”

“How many students?”

“29.” Harry replied easily. He had looked at the list of students often enough, waiting for everyone to arrive for meetings.

“All your year?”

“Mostly, Sir, also seven who were 7th years, one 6th, two 4th, and one 2nd year.”

“Who taught?” Snape suspected Granger although he was aware that she had a relative weak point for Defence.

“Oh!” Potter rubbed the back of his neck awkwardly. “Erm, I did, actually, Professor.”

Snape stared at him for an uncomfortably long time. They both jumped at the sound of a small explosion in the Great Hall. Blasted Cards club.

“Come, Potter.” Snape plucked the piece of parchment out of Potter’s hand, folding it down and returning it to his pocket.

Potter frowned, “But Sir, all of this…”

“Leave it. Filch will have his next miscreant complete it.”

Harry shrugged, not entirely convinced that he was not being dragged off for something far worse.

“Where are we going, Professor?”

“I require a full list of which spells were covered, and when. Who managed the patronus, how many corporeal?”

“Oh.” Potter was not enthusiastic.

“Also, I may require you to supervise some practical sessions in class time when I am occupied with small group tutoring.” Snape continued. “Since you are clearly so distracted during daily work.”

“…yes, Sir.” Harry was unsure whether this was a trick.

“I require straight O’s in Defence for this to continue.” Snape added, “As well a full understanding that the Headmaster is requiring me to allow this.” He paused while Potter thought this through.

All of this had been news to Snape, which meant Dumbledore knew nothing of this new arrangement, which then meant that Snape was making this arrangement for his own benefit. Harry supposed it would be good to have a bit more of a challenge in Defence, and if that meant helping his friends out while Snape was busy bringing the Slytherins up to speed then all for the better, really.

Harry controlled a small grin which was threatening to appear on his face. “Alright, Professor Snape.”