Sirius arrived back to headquarters to find Lily making a fry-up for him, and Catherine sipping a cup of tea, an empty plate in front of her.

"Alive and well, then?" Lily teased as he waved, grinning. "Where did you sleep last night?"

"My cousin lives near the drop site. She put me up. Smells delicious."

"Oh, is that the paper?"

Sirius nodded, dropping it on the table. He'd picked it up from the owl that arrived almost exactly as he did. He hated reading the news anymore, but it was best to keep informed.

Lily set down his plate of food and was just grabbing a cup to pour him some tea when she gasped and dropped it, the ceramic shattering. She quickly cleaned up and mended the cup while Sirius turned the paper around to see what had shocked her. He opened it up and saw the headline, saw the picture of the Dark Mark glowing sinisterly in the sky above a very familiar house.

The McKinnon family home, all six dead. His stomach seemed to have dropped out from underneath him. This was why her family hadn't reported anything. There was no family left to report. They lived in a cottage outside a village far enough that no one would have noticed anything strange. Apparently a friend went by to ask them over for tea and found the Mark still hovering, called in the Aurors right away.

"Even the children," he said to Lily, who was, sniffing, trying not to cry.

"What?" Catherine asked, glancing at the paper. "Oh. McKinnon. That's Marlene's surname, isn't it?"

Sirius nodded, and Catherine soaked in that Marlene was dead. She wasn't crying, didn't seem excessively moved, but she was definitely sad about it.

"What's that?" Catherine asked, tracing her finger across the picture of the Dark Mark. "Strange symbol."

"The Dark Mark," Lily said. "Voldemort's supporters put it above houses they've hit to create fear."

Catherine frowned at it, tracing her finger over it again and again, and Sirius watched her, feeling a strange and paralyzing foreboding. He had a horrible feeling that she was remembering something, and he wasn't sure he wanted to know what it was if it was tied to the Dark Mark.

"There's something familiar about it," she said softly. "Like…like maybe I've seen it before, but…but not like this. It was dark on light, like…like a drawing or a…." She pursed her lips, closing her eyes. "Not the whole thing. Just the bottom of it, just this part here." She wasn't looking at it, but she was pointing at the bottom curve of it.

"Over your home?" Lily asked encouragingly.

"No," Catherine said, squeezing her eyes more tightly shut. "There's no house. I think I'm inside somewhere. Not here. It's…" She shook her head again. "I can only see the bottom, and there's something light behind it. It's dark. Maybe black, maybe like a really dark blue or brown."

"The Mark is green," Sirius said softly, frowning. "Even if it was daylight out. It's a green sort of cloud mist thing."

"Great descriptor," Lily said dryly. "Just try, Cate. Do you know why you can't see the whole thing?"

Catherine rubbed her temples, and Sirius glanced up at the clock. People would start arriving for the meeting soon, and he was supposed to get her to her bedroom and secured so she couldn't hear anything. But if he disrupted her now, she might not remember it again later, not as clearly. He hesitated, glancing at Lily, who was watching Catherine intensely.

"There's something covering it," she said, sounding much more sure of herself.

"Like blocking it?"

"No, covering. Over it, like… Like an umbrella covering someone's face or a sofa cover that doesn't make the floor or…." She shook her head, growling slightly with frustration, and Sirius was surprised to find that the slightly feral sound aroused him. He bit his tongue lightly in an effort to focus.

She continued to try to reconstruct the scene, sights and scents, anything that would help, but she was getting very little progress and only growing more frustrated as Sirius finished his breakfast and several early Order members arrived. The arrivals always looked initially puzzled as they entered and found Catherine sitting there, but none argued when they realized Lily and Sirius were questioning her about a memory that seemed to be emerging. Peter looked puzzled when he and Moody came in last of all, but before Mad-Eye could object, Dumbledore held up his hand and gave the Auror a stern look. The Prewett twins started listing all the things other than a sketch that could be dark on light and a picture.

"A photograph. An etching?"

"An advert."

"Word art."

"Stained glass."

"Stained glass? Bugger all. Book cover. T-shirt."

"Who would have a t-shirt of the Dark Mark? Tattoo."

"Tattoo," Catherine said, her eyes opening with shock. "Peter's tattoo."

Sirius laughed. Peter didn't have a tattoo. If he'd gotten a tattoo, they would have all known about it, teased him relentlessly. It would have been a good source of amusement during the stag night. But Catherine looked quite sure of herself, and the laugh died on Sirius's lips, and he turned to Peter, who looked a bit pale, but otherwise his normal self.

"What tattoo?" Lily asked.

"He was handing me something, and his sleeve shifted a bit, and it was on his arm."

"Which arm?" Dumbledore asked.

"Left."

Mad-Eye grabbed Peter's arm roughly and yanked the sleeve up so forcefully that the fabric ripped, and Sirius thought the world stopped in that moment. There, on Peter's pale forearm, was a perfect, detailed rendition of the Dark Mark, as a burning black tattoo, just like Catherine had said. He looked up at Peter's eyes, almost hoping to find answers there, but it was like looking at a stranger. Not the sweet, bumbling, eager little boy Sirius had grown up with, been friends with, almost brothers. A stranger stood there, and he'd been spying, and if Catherine hadn't seen a small part of the Mark on his arm and recalled it, he likely wouldn't have been suspected.

Because who would have ever suspected Peter of deception?

"What's that mean?" Catherine asked in a small voice, but the tremble in her words told Sirius that she had a pretty intelligent guess.

"It means we've found our mole," Mad-Eye growled, pulling Peter out of the kitchen. "And he and I are going to have a little chat. We'll use the linen closet, Albus. You won't hear a thing. Carry on as usual."

Dumbledore frowned but nodded as Peter was led away, and the Order sat around the kitchen table in silence, everyone a bit pale.

First Marlene dead, now Peter as a spy. The world had seemed such a different place when Sirius woke up that morning.

"I'm sorry," Catherine said, nervously. "I didn't mean to cause a problem. I just…. Well, he was in a hurry before the wedding and I guess he didn't think I'd seen enough—"

"The wedding?" Sirius asked, his blood boiling, as he glanced across at Remus who looked like he was going to cry, and James who looked like he was about to sick up on the table.

"Yes."

She'd seen the Mark before the wedding. Peter sold out Lily and James's wedding of all things. He'd shared drinks with them in the night expecting for them all to be dead by the next night.

"I'm going to kill him," Sirius growled.

"No, Sirius," Dumbledore said softly. "You will escort Catherine to her bedroom, and you will return to the meeting. Alastor knows what to do with Mr. Pettigrew. We will need new headquarters, of course. For the time being, my dear, you will stay in Sirius's flat, if that's not inconvenient."

Sirius shook his head, not really registering. It sounded perfectly reasonable to him, and he got up to put Catherine in the bedroom, his hands shaking.

"I'm sorry," she said, brown eyes wide as he went to shut the door, and he paused. It felt too much like slamming the door in her face, and he just stared at her for a moment.

Then he said, "Cat, you've got nothing to be sorry for. If anything, you probably saved a lot of lives, maybe including mine. So thank you."

Without thinking about it, without really thinking or processing anything, he pressed a kiss to her lips briefly, then closed the door and hurried back into the kitchen, anxious not to miss a word of what was shaping into a very important meeting indeed.

/-/

Catherine felt too nervous to go out and tell Sirius that he forgot the spell to block sound, that she could hear everything in the meeting. Mostly, she was too far away to hear anything more than the sound of voices anyway, but when the door closed up the hall from the linen closet, when Mr. Moody did whatever he was going to do with Peter, who made no sounds, and rejoined the meeting, that was when the sound became very loud.

"That's one snake out of our midst."

Catherine closed her eyes, but the image of that tattoo was so clear in her mind, the snake coming out of a skull's mouth. She shivered. She didn't think she liked snakes much.

"She's not, Mad-Eye. If she was some kind of sleeper, as you've claimed, why would she give up Peter?"

Sirius's voice. Angry, frustrated. Then Lily said something more softly, and Catherine couldn't make it out.

"Well, he wouldn't give up the other spy, would he?" Mr. Moody roared. "And it's very likely they thought he was running his course of usefulness, that she was supposed to give him up at some point to cement her own credibility, get our guards down. Constant vigilance!"

"She's not a spy!" Sirius cried. "She's a scared girl who doesn't even know her own last name for Merlin's sake! She can't even cook bacon!"

There was something in those words that stung at Catherine, and she couldn't get her hands to stop shaking. She looked around the room, trying to think over what she was hearing even as she tried to block it out. Someone else was speaking, softly again. Perhaps Albus, or maybe the kind man named Doge.

What better way to hide a spy than the spy not even knowing what they were? Easier to eliminate memories than be discovered in falsehoods. But she didn't even know what her mission was supposed to be.

But memories could be triggered, a nasty voice in her head told her, and if she met with a trigger that awakened some kind of programming, some kind of past that made her dangerous to the Order, to Lily and James and Remus….

To Sirius.

She closed her eyes so tightly that they ached, but as many times as she told herself that she wasn't a spy, she couldn't be sure, because until she had her memories back, either man yelling in the kitchen could be right.

If Sirius was right, and she ran away for no reason, then the worst thing that could happen was she might die the way the lost and the mad die pointless, faceless, nameless deaths on the street. The number of unknown bodies in the list of the dead was enough to tell Catherine that she might die such a death.

But if Mr. Moody was right, if she was some kind of spy, and she didn't leave before she hurt someone…

If anything, you probably saved a lot of lives, maybe including mine.

To save his life and then to maybe end it. She didn't want to hurt them. She didn't want to hurt Sirius. She began to struggle to breathe, and she looked around the room, dizzy. She didn't need much to survive, theoretically. If she waited until the others left, took some food, a jacket, shoes, she could walk out and survive for a while, until she found more food. It had to be before nightfall, because then she and Sirius were supposed to move to his flat, and she couldn't leave from there. It seemed more terrifying, trying to lose herself in London versus the woods. After all, she was found in the woods. The closest thing to a home that she knew.

She spent the rest of the meeting trying to breathe, trying not to cry, but everything seemed so impossible.

/-/

Sirius was packing up the bathroom with shaking hands as he heard the sound of someone in the kitchen. For the briefest of moments he told himself it was just Catherine, but they'd already eaten dinner, and she was supposed to be packing up her room. He pulled out his wand, dropped the soap he'd been holding into the bathtub, and crept into the hall.

She wasn't in her bedroom. The door was wide open, the light off, and no sign of her. As he moved toward the front of the house, the sounds in the kitchen stopped, and the kitchen door opened. Whoever it was, they were going to leave, maybe with an unconscious Catherine in tow. Sirius could feel his heart pounding at the base of his jaw as he hurried forward, and he stumbled backward slightly with surprise to see Catherine there, an old rucksack from the closet in hand, wearing a jacket.

"That's all you're bringing?" he said, confused. "Cat, what were you doing in the kitchen?"

She blinked at him, stunned, and her mouth worked for a moment without sound. It took him a split second to realize, when she began to tremble, that she wasn't packing to go to his flat.

"What are you doing?" he asked, wincing internally at the stern voice he was using, and the way she shrank at it. He felt like he was yelling at a wounded animal, and he hated himself for it, but the words of Mad-Eye were ringing in his ears.

"I don't want to hurt you," she whispered, eyes wide.

"What?" he asked, stunned. Was Mad-Eye right?

"I heard Mr. Moody," she said, her eyes filling with tears, her hands trembling. "What if I'm supposed to hurt you? What if I was sent here to hurt you? I don't want to hurt you. I should go."

The realization that he'd not remembered to keep her from hearing the meeting in all the chaos with Peter hit him, but not as hard as the realization that she was willing to leave the only safe place she had, the only thing she knew, just to not hurt him.

Them. Not to hurt them.

"You've been so kind," she said, a few tears leaking onto her cheeks. "And you've done so much, and I don't think I could live with myself if I hurt you."

Sirius told himself that those were plural you's, that she was talking about the Order, but every time she said that word it sounded like she was speaking just to him, and he felt a curious sensation of loss at the thought of her leaving him.

"Where would you even go?" he asked, taking a step forward. When she didn't back away, he came closer, taking the rucksack, setting it on the ground. She didn't fight, and he took her hands in his hands.

She began to cry. She didn't have anywhere to go, and she knew it. She was just going to walk out into the woods with a bit of clothes and some food, to walk out of his life forever. Did she think he wouldn't care? That he wouldn't look for her? He pulled her into a hug, holding her trembling body against his chest as she tried to calm herself.

"Mad-Eye's paranoia is legendary," he said gently. "If he could check everybody's arm three times a day and give us truth serum interrogations every morning for breakfast, he would do it. The kind of magic required for what he's talking about is insane, Cat. They could do it, but it's a lot of work and a massive risk on their part. Plenty of ways for it to backfire." She gripped at his shirt and he kissed the top of her head without thinking about it. He thought she might have relaxed slightly in his arms, but maybe that was wishful thinking.

Still, he kept speaking.

"The last thing I want is to lose someone else right now," he said. "Peter was my friend since eleven, almost a brother. And I've lost him, for the rest of my life. I don't think I would know what to do if you left me, especially right now."

She looked up at him with eyes so wide, shining from the hall light and the tears.

"What if he's right? What if I'm a spy?"

"Then we'll figure out what to do later," he said, trying to tease, tapping her nose, wishing he knew what he would do if that were true. "But now, you're not, and you haven't got anywhere else to be. So shall we go to my flat, please? And promise you won't try to leave me in the middle of the night?"

She hesitated, but she agreed, and Sirius trusted her like he didn't think he trusted much of anything at the moment.

/-/

Peter did not open his eyes immediately. He tried to remember what had happened, how he got to be laying down on what felt like a cold stone floor. Marble, possibly? The smell of the place was familiar, but he was too groggy to place it.

Mad-Eye interrogated him, although Peter really didn't recall much of that. He strongly suspected truth serum. He wasn't sore enough for torture. But how did he get to where he was?

Wryly, he thought that perhaps Catherine's sufferings were contagious, but then a high, cold voice spoke.

"I know you are awake, Wormtail."

Peter shivered. He wished he'd never told the Dark Lord of that particular nickname. He'd never liked it to begin with, and to hear it in that voice….

He opened his eyes and looked up at the Dark Lord. He was on the floor of the entryway of Lestrange Manor, a place he'd been to a lot lately, it seemed. Only not from down here. Everything looked different from floors, and few knew that as well as Peter. In rat form, the world was a different place, and if he didn't always keep his wits about him, he would already be dead.

"You were delivered with a note attached to your cloak," the Dark Lord said. "A discovered spy doesn't have much use, now, does he? Especially not with other things we have in motion. Of course, I hadn't wanted to put them into motion so quickly, but you're of little use to me now."

Peter's heart beat frantically, so violently that he could feel it in his ears. It seemed the only thing he could hear as the Dark Lord raised his wand. His vision was blurred, his hearing not functioning as it should, but he knew the incantation anyway. Even through the eyes he closed tightly, he could see the brilliant green light that filled the room, and then he saw nothing.

A/N: So, we don't have any BIG clues about who Catherine is, but there's my first big change of the story! I'd love to get y'alls thoughts on Peter, on Catherine's mysterious situation, on what life will be like now Sirius and Catherine are holed up in a London flat together instead of a house in the woods with people coming and going.

Review Prompt: If you could pick anyone from this era for me to write in their POV, who would it be?

-C