Written for the "possession" square of angst_bingo. This is probably the least angsty fic I'll be writing for bingo. I decided to expand on the "folie a deux" prompt that I wrote for my 300 drabbles a while back.

"Today's a slow day," Jack announced. "So that means we're all going to get caught up on paperwork and things we've left unfinished."

Owen groaned. "But I—"

"You're finishing up your forms and anything else."

"Fine."

Ianto slapped his knees and stood up. "All right. Let's buckle down, then. I'll be up in a minute with all your papers."

Ianto actually ended up running around for a good hour, sorting out papers and rolling his eyes at Owen's snarking. Tosh pulled a thick manila folder of papers closer to her—and her pile was the smallest of the team—and got to work.

"Listen," Owen announced after a few long hours of work-heavy silence. "I need a break. Gwen and I are going out to dinner, anyone else want to come?"

"I suppose I will," Ianto sighs. "I haven't eaten much today, anyway. Tosh?"

Tosh shook her head. "No, I'm nearly finished. You go on."

"Jack?"

"No, I'm good. I've got some calls to make. Have one on me, though."

"Will do." Owen nodded. "See you later."

The cog door claxons screeched loudly at the exit of the rest of the team, and then Tosh was alone. She sighed and picked up her pen, resisting the urge to chew on the back of it. It was a bad habit she'd nearly kicked, but sometimes she slipped up. She was glad she now only found a few mangled pens in her drawer, instead of every single one being gnawed to bits.

Half an hour later she was finished with her paperwork and bored. She tapped her pen against the table and sighed. She doodled for a little while. Then she did a Sudoku. The tiny window of CCTV in the corner of one of her screens caught her eye. She could save herself some time and trouble and go through the Hub CCTV to delete what she didn't need.

She opened up the CCTV history and began scanning through the footage. Ten minutes later, she sat straight up and squinted at the screen. Strange. She flicked through the footage of the day before, then two weeks, then five weeks, then twelve. She could feel her breath speeding up, panic spreading through her limbs as she realized what was wrong, just how in trouble they all were. She stared wide-eyed at the screen, willing it all to be fake.

"What's wrong?"

Tosh jumped, quickly closing the window and wiping any expression from her face.

"Nothing."

"Really? Looks like something."

"You. Your not in any records, reports or CCTV footage before two weeks ago. You're not our leader. You don't exist."

Jack had the decency to look offended before a slow smile spread across his face. He shrugged and held up his hands in a 'what can you do?' gesture. Tosh stood up, hoping she looked more confident than she felt.

"What. Are. You."

Jack sniffed and looked off across the Hub, then smirked back at her. "I live by feeding off of memories. And you all have such interesting memories, such unique minds. It's delicious. And you can't be allowed to kill me."

His hands descended on her.

"Remember."

"No!"

Oh god. Oh god, she was a killer. The memories of countless men and women flashed before her eyes. Sitting in a bar far away from the Hub, dressed immaculately, smiling coyly as she sipped her drink. Waiting for a man or a woman to start flirting, waiting for them to buy a couple of drinks, waiting for them to take her home. Sliding into their bed, but not before slipping a knife out of her purse. Slashing their throats and grinning over the thrill of the kill before slipping away. She worked for Torchwood, her prints were no longer in any database.

"No, no, no, no." She clutched at her head as Jack manhandled her onto the floor.

"Oh, yes. Trust that memory of yours. You know who you are. Remember. I saw you. I helped you. Remember?" Her body jerked and shook under Jack's touch. She remembered her surprise at seeing him, the excitement on his face. She remembered the little wave he gave as he left, his left arm still spattered with blood. "Your secret is safe with me."

"Oh, god."

She was silent at her desk. She had been watching her colleagues all day, wondering if any of them suspected what she was. But they seemed oblivious, and she didn't know whether to be happy or terrified at that. Jack continued to lead the team with a grin and a spring in his step. He threw knowing looks her way when no one else could see and she shrank away from him.

Jack knew what she was, and she was so scared that he'd tell the others. She watched them for a week, but they seemed none the wiser as she shook at her desk and lay awake in her bed at night, tears in her eyes. The lies, the secrets, the horribleness of it all was eating her up inside.

She wandered down into the depths of the archives one evening, trailing a hand along the cool stone wall. It was dark down here, dark and creepy and reminded her of alleys and of the light fading from her victims' eyes. She shuddered.

"Ianto?"

"Over here," he called. She wandered through the shelves to find him crouched against a shelf, rifling through a box of files. He looked up at her. "What's wrong, Tosh? You look like you've seen a ghost."

"I-I need to talk to you."

"Sure. What's wrong?" He took her gently by the arm and sat down beside her on the ratty little sofa in the corner of the archive room. He gently rubbed her back with a hand.

Something inside Tosh snapped and she buried her face in her hands. "I need help!" She wailed, unable to stop the terror and confusion from manifesting themselves in her voice. "I'm a killer, Ianto! A killer!"

"What are you talking about?"

"I've killed so many people! I'm a monster."

Ianto turned to her and gripped her shoulders, a frown on his face. "You are not a monster, Tosh. You could never kill anyone. No one innocent, anyway. I don't believe a word you're saying. You didn't kill anyone."

"I did."

"I don't know what's going on, but I think you're being manipulated. Wait here."

She waited. There was nothing else to do. She was a killer, and nothing was going to change that. Ianto came running back, a box in his arms.

"What's that?"

"It's a lie detector, Tosh. I don't believe a word of what you're saying." He set it up carefully, clipping a wire onto her pointer finger. "Everything else is remote. Come on."

"What are you going to do?"

"You're going to tell me what's going on." He sat back on his heels and nodded. "Go ahead."

"I killed them." Tosh whispered hoarsely. "I killed them all. Men, women. I sat in bars and flirted with them until they took me to their homes. Then I slashed their throats. I watched them die. The life fading out of their eyes. I loved it."

"No. I don't believe you. Something is wrong." Ianto yanked the clip from her finger and it drew a bit of blood where it scraped against her skin. "Where were you when you remembered all this?"

"On my computer. Checking through CCTV."

"Let's check through CCTV, then. Something must have happened to you." He ran across the room. She stayed on the sofa, staring into space. She was a murderer, a horrible cold-blooded killer.

Ianto came running back across the room and grabbed her hand, hauling her up into a standing position.

"What—"

"Come here. Just come here and watch this." He pushed her into the chair at his desk and clicked play on the CCTV.

She watched the grainy video as Jack shoved her onto the floor and placed his hands on her head. "Remember!"

"No!"

Everything slammed back into Tosh's head in perfect clarity. She clutched at Ianto's arm.

"He's not on any CCTV before about two weeks ago. Ianto, he's not our leader. I don't know what he is, but before last week, he didn't exist in the Hub."

Ianto's face looked grim. He closed the CCTV footage. "I know what he is."

"What? Can we get rid of it?"

Ianto pulled a file off of a shelf and plopped it in front of her. "He's a creature from the Void. It's called a Cognijia. A memory-eater. We can kill him if we forget he ever existed for us."

"What about Owen and Gwen? How will we get them to believe us?"

"We'll show them the CCTV."

"But then he'll know!"

Ianto shook his head. "We'll lock him up before we do. It's okay, Tosh. You didn't do anything. It's going to be all right." He pulled his gun out of a drawer in his desk and tucked it into his waistband.

Jack was cheerfully watching Owen autopsy a squid-like alien, poking good-natured fun at his medical skills. The click of a gun being cocked silenced their banter.

"Ianto, what the hell?"

"Shut up for a second, Owen." Ianto snapped. "Jack. Come with me."

Gwen ran down from her station. "Ianto, what are you doing?"

"He doesn't exist," Tosh interrupted. "Until two weeks ago, he never existed in the Hub. He's a creature from the Void."

"A Cognijia. They feed on memories and the longer we remember him, the stronger his existence is." He grabbed Jack's arm and tugged. "Come on."

"But Ianto, you love him! How could you think that?" Gwen begged.

Ianto turned to glare at her. "Then you should believe me even more. He made me think I was in love with him, the way he's made all of us think he's our leader. Tosh, show them."

Gwen and Owen were too much in shock to react properly, and by the time they came to their senses to protest, Ianto and Jack were already down in the cells.

"Look." Tosh played the CCTV from four weeks ago, then the one from two weeks ago. Then she swallowed thickly and played the one from the other night. "He made me believe I was a killer. He changed us."

Gwen covered her mouth with a hand. "Oh my god. We trusted him! We thought he was our leader."

"I know."

Owen's face was set in a grimace. His hands were clenched into fists. "How do will kill it?"

"Ianto says we have to forget he ever existed for us. We have to erase all the CCTV footage of him, erase the last few weeks from our memory, and we'll erase him from existence."

"Exactly," Ianto came up from the cells. "I've got Retcon stored in my desk. Let's convene in the conference room in twenty minutes. I need to do a bit of research."

The three watched Jack pacing in the cell as Ianto hurried down into the archives.

"I thought he was our leader," Owen spat. "I thought he saved me and gave me a new life."

"I trusted him over Rhys! That's awful!"

"We were betrayed by something that never existed in the first place," Tosh said quietly. "It hurts because it's something that happened that also never happened. We trusted a mirage."

Owen shook his head. "He betrayed us as much as our own minds did. He was our leader."

"He wasn't anything, Owen. He doesn't exist."

"Well, he won't in a moment," Ianto's voice cut in dryly. He held up a small pot of pills and they all followed him into the conference room.

"So, what do we do?"

"The file says we have to remember something about us that we feel defines us, a memory from before Torchwood. If we hold onto that memory, that essence, the Retcon should get rid of Jack."

Gwen hiccuped out a half-sob and muttered something about trusting Jack. Ianto placed the Retcon pill in front of each of them. Tosh thought of her first flat, the flatwarming part she never had. She thought of days upon days in front of computers, amusing herself by solving programming problems without books or manuals, taking things apart just to change them a bit to make them better and put them back together. She thought of her mum, her okaasan, telling fairytales while Tosh sat in her lap. She was the first one to take the Retcon pill. She watched the others slowly make the decision and swallow their own pills, then the blackness of sleep overtook her.

Tosh woke to the sound of Owen and Gwen bickering.

"We decided to work together! We couldn't have made that decision together."

"We're missing two and a half weeks, Gwen. How do you know what we could have done?"

"You and I decided we'd lead together after Alan was killed and there was no one to replace him as leader."

"Maybe we did work together on this."

Tosh yawned and stretched and tried to remember what had happened the night before. Nothing.

"Guys, what's going on?"

Gwen turned to her, arms folded over her chest. "We're missing two and a half weeks of memories. Nothing. Nothing on the CCTV, either, or any of our logs."

Ianto appeared in the doorway, holding a tray of coffee. "Something happened that we don't want to remember. I say we don't try to dig at it."

"And I agree with him," Owen nodded.

"Alright, fine." Gwen agreed. "I guess I'll let it go. Jack said I should start trying to let things go sometimes."

Owen frowned. "Who's Jack? Someone we need to know about?"

"Huh?" Gwen looked up at him. "Who? Oh, I dunno…"

Owen rolled his eyes and waved her away. He obviously didn't care enough to pry. "Whatever."

Tosh pushed her chair out and stood. "I'm going to get back to work. I have some things to do, programs to run."

"We should all get back to work," Ianto nodded. "Even if we are missing some time."

Tosh sat down at her desk and turned on her computer. She pulled a pen out of her desk and stuck the end of it in her mouth, gnawing thoughtfully. Suddenly it felt like there was some hole inside her that had never been there before. It was like she had lost something huge and important and not even noticed until now. She felt like she wanted to cry, like she wanted to grieve, and she had no idea why. Her heart felt heavy with the loss of someone or something that must have been deeply important, like she'd just lost her father. Like she'd lost Alan all over again, only worse this time.

But her father was fine. And Alan had been dead for years. She stared at her screen feeling bleak and depressed. Something had been stolen from her life, and she had no idea what it was. It was gone forever, and she didn't think she'd miss something she had no idea of. But this hole in her heart said differently, and she let a few tears spill over for the unknown thing she'd lost and the heavy bleakness in her heart for the stranger she didn't know she loved.