"How much did you tell him?" Olivia asked carefully, eyeing Elliot over the rim of her wine glass. It was her first drink of the night, but he still felt a sudden urge to knock the glass out of her hand; it alarmed him, how many drinks he'd watched her down during their short acquaintance, and he wanted better for her than that. But they had a job to do, and he listened to his better angels, and didn't spill the wine all down the front of her blouse.

"I gave him a hypothetical," Elliot answered. No one, not even Munch, would believe the truth without evidence, but Munch had always been fond of riddles, and Elliot hoped this one might appeal to him.

"A very specific hypothetical," Munch said dryly. "Either the two of you think I'm stupid or you're playing some kind of game here, and either way I have to say I expected from you, Olivia."

In the dim light of the bar Elliot could still see clearly the way Olivia's face paled, her distress palpable in the face of her former partner's accusation, and Elliot found himself feeling suddenly very protective of her, and of one of the few friendships she still seemed to possess.

"No," Elliot said. "No games, and no one here thinks you're stupid, Munch. But you're skeptical, so I didn't wanna come off like some kind of a lunatic. You want the truth, I'll give it to you."

"Elliot," Olivia said warningly. He wasn't sure she'd ever called him by his first name before.

"It's all right," he told her, though his eyes were fixed on Munch. "There's no one I trust more than Munch."

"That's funny, coming from a guy I met ten minutes ago."

"We met twenty-five years ago," Elliot said. That made Munch raise his eyebrows, but there was curiosity in the old man's weathered face, and so despite the unease radiating from Olivia's side of the booth Elliot barrelled forward, and laid the whole story out for Munch, as near as he could figure it. The whole story, starting at the beginning, where Liv and El were partners and Munch was their squadmate, on to Liv's death at the diner and Elliot waking up in interrogation. The fingerprints, the tattoos, Kathy and the kids, this Elliot's death, he set each piece on the board, and when he was finished he leaned back and waited for Munch to pronounce his judgment.

"That's quite a story," Munch said, rubbing at his chin. "You do come off like a lunatic, you know."

"I know," Elliot agreed.

"He's telling the truth, John," Olivia offered quietly. "I saw Elliot Stabler's body in the morgue, Melinda ran the prints herself. It's not possible for the prints to match."

"The prints on file could have been doctored -"

"Melinda printed the body, and Muncy printed him. I know you love a conspiracy, but that's pushing it, don't you think?"

"DNA?" Munch asked.

"Fin took the sample and Melinda's running the test. Should have an answer tomorrow."

"Ok," Munch said, and then he downed his scotch in one go. "Let's say, for the sake of argument, that I believe you. What exactly do you think I can do for you?"

Save me, Elliot thought.

"I don't know," he said aloud. "Explain it, maybe? Maybe if we know how it happened we can figure out how to undo it."

"You want to go back to your own world," Munch said, but it came out kinda like a question.

Did he want to go back? Wasn't that the point of all the research he'd been trying to do? To get him back to the place where he belonged, where Liv and Kathy were both dead? There was no clear answer in his heart; yes, he wanted to go back, but so long as he was here he could still see Olivia's face, hear her voice. Kathy was still breathing, here. But what future could he hope for in this world? Back home he had a job, and the kids who knew him, and Noah, Jesus, there was Noah to think about; Liv would kill him, he thought, if he left her boy alone. But if time passed back home the same way it was passing here, arrangements would surely have already been made for Noah, and maybe Elliot turning up days - or weeks - later wouldn't be good for the kid. It was hard to know for sure.

"Yeah," he said. "I've got responsibilities there. People are waiting for me. And it's not like I can stay here. No one is gonna give a job to a dead man."

"Let me worry about that," Olivia said cryptically.

"Ok," Munch mused, leaning back in his chair, a king holding court. "You asked about string theory. Do you understand it?"

"Kinda," Elliot lied.

"Right." There was something in Munch's face that made Elliot feel like the old man had seen right through him. "So you know all matter is made up of atoms, right?"

That much Elliot remembered from high school science.

"All those atoms, they're all vibrating around. Things we think of as solid - your hand, this table, my glass - aren't really solid at all. There's space between those atoms, a teeny tiny infinitesimal space we can't perceive, and inside that space they're all bouncing around, creating an illusion of solidity. Are you with me so far?"

"Sure."

"Particle physics is the study of particles - the building blocks of matter, atoms and electrons and everything in between and all around. String theory is the idea that those particles aren't points but one-dimensional strings. Most objects we think of are three dimensional - they're defined by height, width, and depth. Stings are only one."

"Wait, I thought the dimensions were space and time and -"

What was the third one? He couldn't remember.

"Time is the fourth dimension," Munch said, shaking his head. "Don't they teach you anything in school?"

There wasn't really anything Elliot could say to that.

"But the question of time matters. I think we're getting off track. The connection between string theory and parallel universes has to do with where the strings are. There's a theory that these strings, these tiny things that make up everything we've ever known, exist in another dimension, that there are more dimensions than we can perceive, and when those strings touch in unexpected ways new universes can be created."

"How does that explain travel between the two, though?"

"Generally speaking, it doesn't," Munch said bluntly. "You understand everything I'm saying is just a guess. An educated guess, but still."

"Sure."

"It may be that the strings that form the whole of you and the strings that formed our dear departed Elliot Stabler got mixed up. Maybe the two of you were close in some other dimension, closer than you ever realized."

"The diner," Olivia said slowly. She'd been quiet, hanging on Munch's every word, and it looked like she understood what he was saying better than Elliot did. "This Elliot was in the same diner in the same town on the same day that our Elliot Stabler was. Our Elliot died, and then this one turned up here."

"That could work," Munch said. "If we imagine time not as time but as a location. The spinning of the earth on its axis, the earth's rotation around the sun, the time can be identified as a fixed point. And in that instant where both universes, both earths, were in precisely the same place, the same time, maybe the two Stablers were standing on the exact same spot on the floor of the exact same diner."

"Hold on," Elliot said. "I didn't come here from the diner, though. I carried Liv out of the diner, the medics came, the ambulance took us both to the hospital, and then I woke up here."

"That is a wrinkle," Munch frowned. "Did our Elliot die inside the diner?"

"On the sidewalk outside it," Olivia supplied helpfully.

"And if he was dead already, even if they took him to the same hospital it would've been to the morgue, not wherever this Elliot went."

"Right, so…so what does that mean for us?" Elliot pressed him as a growing sense of dread bubbled up inside his gut. "Is it still the diner? Do I need to go back there?"

"Even if the diner was some sort of extra-dimensional portal tossing Elliot Stablers back and forth across universes, there isn't an Elliot Stabler in your world for you to switch places with. I don't know what good it would do."

"So I'm stuck."

"Unless it was something else," Munch said. "There's an Olivia in your universe, too. You said she died?"

"Does that matter?" Olivia asked sharply. "I'm still here, I didn't get sent across the multiverse or whatever we're gonna call it."

"Maybe his Olivia's death was a mistake," Munch said. "Maybe the strings got crossed, moved in a path they shouldn't have, and now it's thrown the whole thing out of balance."

That sounded right to Elliot, not because it was necessarily logical, not because it was necessarily sane, but because the idea of Liv dying was so fundamentally wrong that he could believe, rational or not, that it was never meant to happen, that it was wrong enough to upend the very fabric of reality. They weren't meant to be apart, him and Liv, weren't meant to exist in a world without one another in it, and maybe he'd been thrown into this Olivia's path to right two wrongs, to give them back to one another.

"So what do we do?" he asked. "We can't figure out how to get me back to my own world, and now we need to send me back in time to stop Liv dying, too?"

"Life is not a comic book, my friend," Munch told him sadly. "It's a question without an answer. We can sit here and talk about what ifs and maybes all you want but at the end of the day the fact remains we don't have a single clue what any of this is, or how it works, or how to fix it. Some things…some things can't be fixed."

That was not the answer Elliot wanted to hear. He'd been so sure when they turned up here that Munch would have all the answers, but he saw now how unfair that was, to put such a burden on a man who didn't hold the keys to the universe in his hands. It just felt like he did, sometimes, just felt like if there was anything worth knowing Munch would be the one to know it, but in life there were no superheroes, no easy answers, no time machines or magic bullets that could erase the sting of grief and undo what had been done.

It was grief, that flowed over him now, but it was a grief that came with acceptance; he might not ever know how he'd gotten here, just as he might never know the truth of God's existence or his plan for Elliot's life, but he was here. Maybe he could try to go back to the diner, maybe he could spend the rest of his life buried in books trying to find answers to unknowable questions, but he was here, now, and here was where he would stay.

Here, with Olivia.

"Tell me something," Munch said then. "You said you know me. The me in your universe. What's he up to?"

Elliot smiled. "He's back in Baltimore, running a bar. Getting married again."

"That's good," Munch said. "That's good."

But is it better? Elliot wondered. Was the Munch in Baltimore happier than the Munch sitting across the table from him? Which one of them was right; was there even a right universe, a single one where everything happened exactly as it was meant to, or was each as right as the other? Would Elliot himself be happier here in this world, with Olivia, than he would have been at home with their children but without her? Was there any ending to this story that didn't hurt?

"Well," Olivia said. "Since you're going to be with us for a while, I've got an idea."

"I'm all ears," Elliot told her. Whatever suggestion she had he'd hear it; he was here, now, and not going anywhere any time soon.