Lydia had begun a series of equations to deal with events and their duration, which was sort of a crossover with Divination in some respects, but the goal was to use Arithmancy in order to chart out roughly how long ongoing events would last, based on a variety of factors. She had tested it with small things, that she didn't know the duration of, like how long it would take her to finish reading certain books, how long it would take Lily to crochet the hat she had been working on, how long it would take Sirius to notice that she had moved his keys to his bike.

After testing on subjects of varying lengths, she was going to do it on a full map of something that was really significant, the reason she had started the whole project, because if she could predict this she would have a publisher for everything she ever dreamed up, no questions asked.

Lydia Rowe was going to predict the end of the war, using numbers.

Sirius was out for the day with James and the other Marauders, although not doing anything for the Order. That gave Lydia the clarity of mind and time she needed for such a project.

As soon as she gathered her thoughts, Lydia pulled out several sheaves of parchment, carefully laying them out on the hardwood floor, an inkwell in hand as she knelt down beside the parchment she spread out. She licked her lips and selected from her desk her favorite quill for such occasions, dipping it carefully into the inkwell and thinking of where to start.

Lydia had been studying old news stories for a while, taking careful notes, so carefully read and reread that she no longer needed to look at them before beginning her equations from the beginning. The most frustrating and difficult thing as she began the calculations was the immense number of variables involved in this particular case study. She mused momentarily whether she might not be better off using a Muggle calculator, and she bit her lip, wondering if she had one stashed away in her things.

She didn't think so. She had been doing maths entirely by hand since well before she ever went to Hogwarts. It had never seemed quite right to her, to do them any other way, when her own hand was usually faster than the calculator and all the buttons.

It was a very painstaking process, dealing with all the nuances of the war, the careful calculations. There were some variables she could not number, like the members of the Death Eaters, and she had to guestimate to the best of her ability. She hoped that the error involved from those such numbers wouldn't be too awfully large. It was difficult enough to do this process at all, especially so without proper numbers.

But she couldn't very well write to Severus and ask for a headcount. She wasn't sure he wouldn't give it to her, but she wasn't sure he wouldn't think it intelligence from the Order instead, sending her in to spy on them.

No, Lydia would have to make do with what she had, and the calculations began to cover several sheets of parchment. She was very punctilious, knowing that any mistake would be difficult to catch later, or to rectify even if she could find it. These were very complex theorems and equations she was dealing with. At the decent stopping point of having put down all her input, Lydia got herself a cup of tea and brought it with her back to the study, where she began carefully pairing down the equations, trying to see where the end came.

But as she continued to add together the varying factors, even accounting for error, the final numbers only increased at alarming rates until she realized that they were tending very strongly toward infinity.

"No," she groaned, leaning back against the leg of her chair. "No, no, no! There has to be an end! Everything has an end, especially war!"

She set down her quill and began carefully searching for some error, but there was nothing she could find. But the war had to have an end.

Unless…

Unless the infinite number somehow signified not the end of the war, but the end of Voldemort's rule, his new world order that he hoped to institute. Lydia began tracing over her input values, trying to decide if that was what it could mean. Indeed, it could be identified in that way.

Unless something very, very drastic happened, according to Lydia's calculations, Voldemort was going to win. Her heart began to pound in her chest and she wondered if she could start all over, convince herself that the equations were rubbish and abandon the project like there was still some sort of hope.

She rubbed her eyes, trying to calm her breathing so she didn't send herself into a panic attack with no one around to help her. Scrambling to her feet when she could not calm her breathing, Lydia rushed to get the last vial of calming draught they had in the house and downing it without bothering to glance at it or smell it or anything. She knew when she brewed it. It would be fine.

As soon as the liquid settled inside of her she could fell her whole body relaxing and she tried to focus on what to do with the calculations. Lydia decided that the best thing to do was to go and pick up a few things in Diagon Alley that she needed for brewing and come back and think about the equations later. She was obviously in no state to deal with such a mess. So, Lydia grabbed her coin purse and her cloak and set off for Diagon Alley, wand in hand just in case something bad were to happen, as Sirius warned her every time she went out of doors.

She strolled right up to the apothecary, barely glancing around her.

It was when she entered and bumped right into a dark-haired person that she froze, for she would recognize that person anywhere.

Severus turned at looked at her with mild surprise, as though he'd never seen her before. Indeed, Lydia tried to count back and realized she'd not seen him at all in eight months. Why did it feel like it was only yesterday, then?

"Sorry," she said awkwardly, breathlessly. "I should have paid more attention."

He was looking at her pupils.

"Have you taken a calming draught?"

Lydia felt her face flush. Trust Severus to always know if she'd taken a potion of any kind. He was aware of every side effect known to man.

"Ah, yes, actually," she said, moving out of the doorway so that no one ran into her, leading him down the aisle toward the beetle eyes. "I was working on a calculation and the result was…troubling. I didn't want to deal with a panic attack while I was home alone, so I…"

"Of course," Severus said in his smooth voice. Lydia hadn't realized how much she had missed that voice until it rolled into her ears. It was unfair, really, that she had to make such difficult choices. "What are you brewing, then?"

"Oh, I'm just stocking up, generally," Lydia said awkwardly. She knew that he could tell she was making potions for Healing. He could see the ingredients for hundreds of potions and know what was to be brewed, without a hint beyond the ingredients. "We're just a bit low on…everything, really."

Severus nodded, his eyes searching hers. Lydia had the most strange sensation when looking at him, that his eyes were turning liquid before her gaze, and she wondered if there was liquid in the core of eyeballs, and if there was what its viscosity was like.

This was why she hated taking calming draught. Her mind thought of the most ridiculous things, and she found herself feeling embarrassed for even thinking.

"Here, let me help you with that," he said as she tried to scoop the beetle eyes into the bag with one hand, while the bag tried to flap closed. Severus took the scoop from her and she held the bag open for him to pour the eyes in.

"Do eyes have liquid in them?" she asked finally, unable to contain herself anymore.

Severus paused for a moment.

"Beetle eyes?"

Lydia shrugged. She really meant human eyes, but she didn't think this was the time or place to ask Severus such a question.

"There is a fluid, yes," Severus said.

Lydia nodded, pleased to know that she wasn't mad. "Is it very thick?"

"It's like water, really," Severus said, shrugging. "Beetle eyes have a very thick shell that human eyes don't have, so we can crush them and make a paste, but you couldn't do that with a human eyeball."

She frowned, realizing that he must have somehow seen into her thoughts. Severus had mentioned that You-Know-Who did that. Perhaps he had learned as well.

They worked together to gather up the rest of her ingredients, and Lydia realized that he had already purchased his, that he was using her shopping as an excuse to spend a little more time in her company before she went back to Sirius's house and he went back to Spinner's end and they saw each other in what Lydia felt was likely to be another eight months. She had missed this, his closeness, his discussion on the right way to brew various potions, to make various pastes.

"I think that's everything," she finally said, when she could no longer think of anything else she would reasonably be able to use. Severus did not look particularly put out, but Lydia could tell that there was a subtle fall in his countenance. She knew him better than anyone.

Lydia paid for the ingredients, thanking the apothecary before walking with Severus out into the Alley.

"I suppose I really should be going," he said softly. "I…I have a client who wants a potion rather…urgently. The sooner I begin, the better."

Translation: You-Know-Who wanted him to brew something, and if he didn't get it done on the timeline given, he would be tortured at best. As he began to walk away, Lydia called out.

"Wait," she said. He turned quicker than she would have expected, his black eyes glittering but unreadable. "For a calculation I'm doing…. How many…of your colleagues are there?"

Perhaps that was the variable she had gotten wrong. It didn't hurt to ask, did it?

His face did not change expression, but he watched her for a moment, obviously trying to discern what sort of calculation she could possibly be doing that would require that information. Finally, he shook his head and said, "Honestly, Lydia, I don't know. I could name perhaps a dozen on the spot, but there are many more. We are only allowed to know of a small number, in case…."

In case someone was caught, tortured, broken by the ministry or the Order. They could only betray so many people. Lydia knew it made sense, but it was disappointing. She nodded.

"That's fine," she lied. "I understand. I…I should get back. I haven't even started dinner yet."

Severus nodded and they stared at each other a little longer before turning, walking their separate ways. Lydia felt a brief urge to run after him, but what was the point?

No, she steadied herself and Disapparated, glad that the awkwardness was over. At Sirius's house, she knew what she needed to do. She had a purpose in every moment, and she knew she could live up to things that were expected of her. As she went about making dinner, the trip to Diagon Alley and the calming draught had done their purpose: she had forgotten all about her troubling calculations earlier in the day. Just as she was laying out everything on the table, she could hear Sirius unlocking the front door.

"We're here!" he called.

"Good," Lydia said, poking her head out of the kitchen door to see Lily and James standing there, taking off their coats. "Because dinner is ready for you. You all have impeccable timing."

They hurried with getting off their coats and shoes and came into the kitchen as she was pouring some wine. Sirius kissed her gently before sitting down at his place, looking around at the roast and potatoes she had made.

"This looks brilliant, love," he said happily.

"I take it your day went well," Lydia said, almost teasingly. She didn't want questions about her day, but it was difficult because she could hardly ask questions about his.

"Yes, love. It was excellent, thank you," he said.

"Did you buy potions ingredients?" Lily asked, gesturing to the empty bags from the apothecary that Lydia hadn't had time to throw in the rubbish bin.

"Yes, I was running low on a few things," Lydia responded casually. She couldn't possibly tell them that she ran into Severus. That would be a disaster. But she couldn't rightly tell them about her calculations that morning, either. She didn't want to think how Sirius would react to that. "It was a fairly quick visit. I just forgot to throw out the bags when I was done. Don't worry, I didn't get anything unstable or dangerous."

"That's good," Sirius said cheerfully.

Lydia wasn't sure what was going on, but she had the distinct impression that it had something to do with either something that happened while he was out, or something that had been said before they came into the house. She looked around at each of them, and they all bore incredibly happy expressions.

"What?" she asked. "Why are you all acting like you're on drugs?" She paused. "You're not on drugs, right?"

Sirius laughed.

"No, no, nothing like that," James said happily. "Only, Lily and I have some news, and we want to tell you…."

Lydia raised her eyebrows. They were pregnant. No, no, they couldn't be pregnant. Lily was sitting there, drinking wine. So what was going on?

"I'm all ears," she prompted, although she was very anxious.

Lily gave James a nod, and he said, "We've decided we're going to try for a baby."

Well, it was a step off pregnancy, granted, but still a massive bit of news. Lydia just stared at them for a long moment.

In truth, she had rather already thought that they had decided, so it was strange to have them announcing it like everyone hadn't already known that it was exactly what they were going to do. Still, they expected some sort of response, so she smiled and said, "That's wonderful news!"

It felt so ridiculously false. Wonderful news would be pregnancy. Wonderful news would be the baby was born. Lydia just felt absurd, even as the words spilled off her tongue.

Her mind then traced back as they began to celebrate the non-celebratory event, and she thought of the parchment sprawled out across her study floor. She thought of her calculations.

Would it be unconscionable to mention them when her friends were so happy in their decision? Would be to unconscionable not to? Although, Lydia also felt that it likely wouldn't change their decision to have a child, knowing that the war may never end, or that You-Know-Who may win. Lydia still shifted uncomfortably in her chair, trying to decide what she should do about those damned calculations. Her peace had been disrupted by the news, and she could no longer ignore them in her mind.

"Lydia?" Sirius asked, frowning. "Love, you seem out of sorts."

"I'm sorry," she said, forcing an abashed smile. "I did some calculations this morning, and they didn't turn out how I wanted."

"I'm sure you'll figure it out, love," Sirius said cheerfully, kissing her temple.

He didn't understand. He couldn't understand.

Well, of course he couldn't, if she didn't tell him what there was to understand, but how could she? There was so much…so much she couldn't say about her project. If she tried to explain it to Sirius, he would tell her that she was being silly, and that numbers couldn't predict things, in spite of her evidence.

Lily might understand, but it wouldn't change her mind. And, as Lily would certainly point out, numbers could lie. Sometimes, they got it wrong. What if this was one of those times? Why should they live their lives thinking that something was going to happen if it might not? There could be some cosmic event that Lydia's equations couldn't possibly foresee.

And that was all perfectly true, so Lydia said nothing, sitting and pretending to be thrilled while her friends continued to celebrate. When they went on to their third drink each, Lydia began to shift uncomfortably in her chair again, anxious to at least put away her calculations.

She got up.

"What is it?" Sirius asked, touching her leg to try to stop her.

"I've just remembered something I forgot to clean up," she said honestly. "Won't be a moment.

Lydia went out of the kitchen, headed straight for her study, looking down at the parchment still all over the floor. Very carefully she picked the pieces up, one by one, stacking them in a way that would lead to the best recreation of their current configuration. She had a brief thought of numbering them, but decided that was too much. She glanced around the room, looking for somewhere to put the stack, and she decided to shove them into the bottom drawer of her desk, which was largely empty, but for some packets of quills that she hadn't needed to break out yet.

Blinking down at the drawer, she had a sudden urge to burn them, but then, for some reason, her mind moved back to Diagon Alley that afternoon, to her conversation with Severus about eyes, and Severus's own liquid black eyes.

Maybe they would have some use…. Just not now.