It did not take long for Sirius to notice a kind of rivalry setting itself up between two main cliques, with Harry at the head of one and Catherine at the head of the other. One consisted of three boys and a girl, the other four girls and a boy.

"I should have seen this coming, shouldn't it?" Sirius muttered to Remus and Severus, frowning. "I mean, this was always inevitable."

"If you mean," Severus said, pouring himself some water in Sirius's quarters, "that you should have foreseen that your daughter would inherit some of her father's disregard for rules and penchant for attention, and that Potter's son would do the same, then yes, you certainly should have. As for their pitting against each other, I am not certain that will always be the case."

"True," Sirius said, pouring himself some firewhiskey.

Even Lily and James stopped fighting eventually.

The thought of comparing Lily and James with Harry and Catherine caused Sirius to choke on his alcohol and Remus gave him an alarmed, puzzled look. Sirius shook his head.

The teachers were calling it chaos. Catherine was calling it nothing. And the students were calling it the Great Prank War.

Technically speaking, none of the adults could be certain who started it, but if Sirius were betting money on it, he'd blame his daughter. It definitely started between the two cliques, and there had been a major growth of activity outward from there. Catherine and Harry had started out small, with childish pranks of simple practical and magical intent, and their ambitions had grown. Even more importantly, as others jumped onto the bandwagon, older and more talented and hot-headed students had become a part of the mess, and a Ravenclaw fifth year had been put in the hospital wing with a concussion and inverted nostrils that afternoon.

"The question is, what do we do about it," Remus said darkly.

Always the Prefect, Sirius thought with mild bitterness.

If not for that injury, Sirius would have been perfectly happy for the Prank War to continue for the next six years. It might have gone on longer, since Caroline and Aeson would have undoubtedly picked up where their predecessors left off. But things had grown out of hand, and the last thing Sirius wanted was for Hogwarts to be unsafe, not while his daughter was there.

"Nothing," Severus surprised the other two men by saying. "We do nothing." He set down his water as they raised quizzical eyebrows. "If you try to interfere before things burn themselves out, as they will undoubtedly do, you risk causing students to be sneakier, which some will do, and that may stop students from coming forward in the event of a true emergency. No doubt if something happened to Catherine you would want her friends and opponents alike to feel safe reporting the incident in question."

Sirius's stomach turned. For the moment, he supposed, he could handle doing nothing, but he would not do so willingly. If anything, he would be eager and anxious to keep an even closer eye on Catherine. Nothing was going to happen to his little girl, not while there was breath in his body.

"So," Severus continued, pouring himself more water. "I wanted to have a word with you, Black, about your daughter."

"What about her?" Sirius asked, hesitant.

"For reasons I cannot begin to fathom," Severus said, smirking, "she seems to have an incredible aptitude for my subject." Sirius's face quickly expressed his surprise. "Indeed, it is most shocking. However, I wish, with your permission, to tutor her independently. I believe she shows true promise as a Potioneer, and someday she could do very similar work to that which Lily does, if she is so inclined. I want, with your permission, to give her the best possible start down that path."

Sirius had hoped Catherine would excel at his best subjects: Transfiguration, Defense, Herbology, History. She did well in them, but he'd never expected her special talent to be Potions, of all things. Even more shocking was that Severus was willing to go an extra mile to help her.

"Alright, then," he said, shrugging. "Make sure she's still got time to be young, but extra lessons should keep her safer for a little while more each week."

Remus snorted with amusement, but the three men each poured themselves more of their drink of choice, and conversation turned from the students to Lily's latest updates to Wolfsbane.

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Lily sat down with Dorcas, a little surprised to get a call to meet her old friend mid-week, but mostly anxious that whatever they were meeting about would be troublesome or even dangerous. She worried about their children, and about Sirius, who was bound to be dragged in somehow. It was the last thing he needed.

"Lockhart is a small fish, isn't he?" Lily asked without preamble as she poured their tea. "You're going after someone bigger."

"I'm going for the top of the ladder," Dorcas said grimly. "Not Fudge, don't give me that look. No, but it's not far off. Lily, promise me you won't freak out when I tell you who I'm going to try to flush out."

Lily's eyes narrowed but she nodded her promise. Dorcas still hesitated for a moment, hiding behind a long sip of tea.

"I think I have to cut this thing off at the head, and I think the head may be Dolores Umbridge."

Lily almost dropped her cup.

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Hermione wanted to be able to say that none of it was her fault and wash her hands of the matter, but she knew better. She'd seen Harry or Ron use spells she'd discussed with an apparently innocently curious Neville. Just like she'd seen Ginny and Catherine use spells that their Ravenclaw friends researched for them.

"This is getting out of hand, Neville," Hermione said darkly when the Ravenclaw girl returned to school, finally released from the Hospital Wing. "What if something terrible happened to one of you?"

The rims of Neville's ears went pink and he said, "One of who?"

"You," she said, shrugging, feeling her own cheeks go slightly pink. "You know, you boys. Those girls. Creevey. I realize you can't be held responsible for the behavior of the rest of the school, but what if Ron accidentally hurt his sister, or one of you lot hurt Catherine Black?"

"Of all the people who might get hurt," Neville said earnestly, "we had better wish on everything we can think of that it's not Kitty."

Hermione was startled by the intensity of how he said this, but she nodded. She supposed that if there was someone not to injure, it was the child of a professor, even if she was one of the main reasons all the chaos started in the first place. From what Hermione had seen, Professor Black was devoted to his daughter, and the idea of something happening to her could turn their jovial professor into something else entirely.

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Remus's eyes narrowed as he saw the book Luna Lovegood slipped Catherine coming and going outside his classroom. It was far too advanced for their level of magic for a start, but he happened to remember using that book in a prank war or two of his own, and his confidence in Catherine's discernment was not such that he felt safe letting her go through it.

She did have a fair amount of her father in her, after all.

"Kitty," he said firmly, gesturing for her to come forward.

Merlin, she was good at feigning innocence. Had she seen her father make that face, or was it somehow genetic? Whatever the reason for her using it, Remus found the likeness to be uncanny.

"Yes, Uncle Remus?" she said, smiling at him sweetly.

His eyes narrowed, and her face fell slightly.

"Book," he said firmly. "No, the one you shrank and slipped up your sleeve."

Ryana Cotton gasped, impressed at this feat, and Remus hoped he didn't look too impressed. It was magic beyond her level, and when she reluctantly produced the book he found that it was also done perfectly.

"See me at lunch, Kitty," he said, his voice low. "And maybe we can keep this between us."

She grew pale at the suggestion that he was going to bring her father into things if she didn't cooperate, and with her nod he knew she would do what he asked of her. That was her mother in her.

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Severus found out about the book from Remus at lunchtime, and promised to keep the matter from Sirius unless Catherine showed any further trouble, but he had his extra lessons with her that evening, and he decided to take the opportunity to place a bit of fear in her. Knowing her temperament, it would not stop her behavior, but perhaps it would temper it.

"Come in," he said, as usual. "Sit down. Get out your cauldron."

Catherine blinked with surprise at this steady set of instruction, but she nodded and did as she was told, sitting down and looking up at him expectantly.

"Every potioneer has a signature, Miss Black," he said softly. "Did you know that?"

To her credit, she stayed outwardly placid as she said, "No, sir."

Inside her head, though, he could see that she was slightly panicked, thinking back through her recent memories.

"It would be to my disadvantage as your teacher," he said softly, "for me to tell you what your signature is, but I assure you, Miss Black, you have one." She swallowed. "And when Mr. Harper came to me belching rainbow vapor, and when I examined his pumpkin juice, imagine my surprise when I found your signature in the rather advanced potion involved in his predicament."

He was irritated when she smirked slightly and said, "Sir, I doubt very much that you were surprised. You know almost everything that happens here."

Perhaps more sternly than was necessary, Severus said, "When I was young, I used my skills with brewing for things I should not have, and at first no one was hurt, and then a few people were ill, and then a few more, and then people died. Do you understand me?"

Catherine paled, and he had to remind himself that she was only a child, only eleven years old. She wasn't being cruel, just having fun.

But that had been how James Potter saw his behavior, and a young Sirius Black, and a young Peter Pettigrew, and how much did it really take for one of them to turn skills in "fun" to the services of the Dark Lord? Whatever penance Severus had to pay in his life for the things he had done, the least he could do was give Catherine Black a small scare to help her think twice about her behavior.

"You are very talented," Severus said softly. "And you are very clever. Making Mr. Harper belch rainbow vapor is not a quality use of your time and talents, and is not good for your character. Regardless of how your Head of House or your friends or even your father think of you, think of this incident, I am very disappointed in you, Miss Black, and I trust you will do better in future not to misuse the education I am investing in you. I am not taking extra time out of my very busy schedule to teach you so that you can waste your talent on such trivialities. Are we quite clear?"

"Yes, sir," she said, her voice smaller than he'd ever heard it, and he was satisfied to begin her lessons.

It was not until she left for the night that he realized his mistake. He'd told her that he did not want her to misuse her talents, her education in Potions. Catherine was no fool. She would never misuse brewing again, but he had not said anything about wandwork.

He closed his tired eyes and sighed. Just like her bloody father.

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Cora sat down on a chair in the back yard, frowning up at the stars. She tried to remember any of their names, but she could only remember the ones she saw in the earliest days of summer. If any of those were still out now, she couldn't find them, and that frustrated her.

Uncle Gideon sat down beside her, at her feet, looking up to where she was looking.

"What's up there?" he asked.

"I can't remember any of their names," she said, feeling slightly defeated. "Can you?"

"Ha, no, I don't, love. I was never any good at Astronomy. Ask Uncle Sirius. He was always good at remembering that sort of thing. What's been troubling you today?"

Cora shrugged, not thinking about how he couldn't see her from where he was sitting. After a long moment of silence between them she said, "I miss Rhea. I hadn't realized how much I would miss her, but between her being gone and Mum never being home, it's harder than I thought it would be."

Uncle Gideon nodded, resting his head on her arm. His hair was soft and his skin was warm where it replaced the cool night air. She should have put on a jumper before coming outside, but she hadn't thought of it.

"You're a very brave girl," he said gently. "It'll be your turn to go soon enough, my dear. You'll see Rhea every day and you'll probably be quite sick of her and not miss me at all."

"Never," Cora insisted with a gasp. He chuckled, but she could hear the sincerity in his voice. She wondered what was bothering him, but she supposed that it was perhaps that she was growing up, and he wasn't ready for that.

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Dean pretended not to listen as Harry, Neville, and Ron examined their battle plans. He pretended not to listen because he was nervous about getting involved, but also because he knew that if he did get sucked it, it would be to help the girls.

He liked his roommates, but Dean knew winning quality when he saw it. Harry was brilliant at Quidditch, but from the pranks displayed thus far, he was out of his depth for creativity and sheer willingness to take things to the next step. He was always saying in a hushed voice, to Neville, how he couldn't hurt Catherine with whatever he was up to, that no matter what they did, Catherine couldn't get hurt. Pride dictated that the boys continue while they were losing to the girls, but they weren't willing to do what was truly necessary to win.

Dean was almost certain the girls had no such qualms.

On the whole, he thought he would have been much happier without the Great Prank War. It would have made it easier to get to class, to have a quiet moment to study, to sleep in peace and not in a war room. He was actually starting to look forward to classes as a kind of safe zone.

The door burst open violently and Seamus came in clutching at a stich in his side, gasping for air. The other four boys sat up straighter, looking at him, concerned and wary. He'd left the door open, so either he was being careless because whatever he was about to say was important, or he was the instrument of an ambush. Dean didn't want to think what would happen if Ginny found some way to lay an ambush in their dormitory.

Finally, Seamus found his breath enough to close the door and speak.

"Ginny and Creevey just left the dormitory," he said eagerly. "I waited until they were done speaking because they didn't see me, and I wanted to hear everything."

Harry stood, scattering some of his battle plans based on their maps of the Goblin Rebellion of 1346, from their History of Magic homework.

"What did they say?" he asked.

"Ginny was really upset," Seamus said grinning. "Apparently Kitty Black had a book confiscated."

"A book?" Dean asked, puzzled. What kind of books were confiscated?

"The book they'd been using for their planning."

This seemed to mean a great deal to Harry, who punched the air triumphantly and pulled mirror out of his pocket, turning it over. He looked at it for a long moment before shaking his head and stuffing it back in his pocket.

"She's too clever," he muttered, his eyes narrowing. "She won't surrender from such a minor setback."

"If that's the book I think it is," Neville said softly, "that's a pretty big setback. And if whoever confiscated it tells her father…"

"It was Lupin," Seamus said helpfully.

Neville and Harry groaned. Apparently, Dean surmised, Lupin would not tell Catherine's father about whatever book it was that had been taken from her possession.

"She'll just find another source of ideas," Harry said, pacing. "I wouldn't put it past the twins to help her, either."

"They're my brothers," Ron argued weakly.

Dean thought that was overstating a matter of familial loyalty. Dean knew that if he were family and choosing between the two, he'd pick Ginny's side. She was youngest, the only girl, and a little bit scary. Plus, Dean would be more afraid of Catherine than Harry any day. And Dean wasn't sure, but he thought that one of the twins might fancy Catherine a bit, so their loyalty was by no means secure.

"I could dig around my family library too," Neville said, although his expression wasn't sure that was a good idea.

"That won't be until Christmas," Harry said, frowning. "We need something we can use now."

The five boys sat in silence, trying to think of a fresh source of ideas. Goblin Rebellions were limited, it would seem.

"We could use the Restricted Section," Harry finally said, a slow smile over his face.

"We can't," Ron said. "It's restricted."

Harry's grin was even wider as he said, "Whoever said we'd be there during the day?"

A/N: The Great Prank War! I've been so excited to get this started. A little way to spice up this year, what with no basilisk attacks. The two cliques are trying to assert their power. Sirius is trying not to be tooooo proud.

Review Prompt: Would you be team Harry or team Catherine? In the prank war.

-C