"Okay, so what we're doing here is making a-a, um, paradox," Fitz said excitedly. He grabbed a wrench and some cables from his backpack and ran back to the side of the generator, kneeling down to look inside the hole he'd cut out of the casing earlier. "We're going to bring younger you, younger Jemma, to where we are in-in the timestream. All of the laws of physics say this shouldn't even be possible. But, um, I've got a good feeling about it."

Jemma, who was standing back just far enough to keep out of his way but close enough to help if needed, rolled her eyes-but she was still smiling a little. "The laws of physics don't take alien technology into account, Fitz."

"I know." He looked up from the generator to flash her a quick smile, then went back to hooking the cables up to the generator's main power source. "Also doesn't take in-in-it doesn't include my, um…unappreciated genius."

A glance back at Jemma showed that she was smiling widely now, and it transformed her face into something beautiful, even with the added years. Skye laughed over the comm, and he heard a noise that sounded suspiciously like Hunter making an exaggerated gagging sound. It was funny in a way, how the sudden loss of the tension between him and Jemma had him feeling lighter and more energetic and confident than he had in almost a year. He still wasn't firing on all cylinders, but if he could hold on to this-if he and Jemma both could, if everything worked and they made it back home-then maybe…just maybe, there was some hope left for them after all.

After Jemma had agreed to help him, they'd gone back inside to finish making the necessary modifications to the generator and come up with a plan of action. Younger Jemma, who they were maintaining contact with through the screen, would pipe up from time to time with comments. It was strange when both Jemmas would talk; it was sort like hearing her in stereo.

"Okay, Fitz, explain this to me one more time," Coulson said over the comm. "So we can get everything ready on our end."

Fitz connected the last of the cables and stood, picking the screen up off of the top of the generator. "Going over everything for Coulson," he told Jemma. Then he held up the screen so he could see her younger self. "Still with us?" She gave him a thumbs-up, looking nervous but eager. Fitz smiled, hoping to reassure her, and started gathering up his tools to pack them away in his backpack. "Right. So, basically, we're changing Jemma's future. Originally, she-um, in the past, her future self-Jemma now-told her that she wouldn't help."

"Now I've changed my mind," Jemma added as Fitz stepped past her to grab his backpack. "I'm helping, even though every law of science says that changing the future isn't possible."

"Yes, except," Fitz cut in as he zipped his backpack shut and carried it back to the generator, "I believe that knowing your own future is-is what helps you to, ah, actually change it."

"That, and being brilliant as well," Jemma said, with just a hint of smugness.

Fitz scrunched his face at her. Was she-? No, of course she wasn't. "Well, there's two of you now, so...yeah. Double the brilliance."

A groan came over the comm. "Bloody hell, is this what they were like?" he could hear Hunter ask.

Skye laughed. "Oh, this is nothing. Wait until they start talking at the same time and finishing each others' sentences."

Fitz felt a small bloom of warmth in his heart; for once, the memories of how he and Jemma had been before the med pod were sweet instead of bitter. "Anyway, we're using the generator to, uh, boost the signal on the tracker, and get a lock on younger Jemma. Then they'll use a shared memory or thought, something they b-both know, to boost that lock." He gestured with the screen. "And since the, um-the walls of the timestream-if you want to call them that-since they're thinner here, because Jemma has a strong-a big presence here, hopefully we can bring her through to where we are."

"And that's the paradox," older Jemma said.

Fitz nodded as he pointed at her. "Right. Having two Jemmas in the-the same place is technically like...cheating. I don't know how long we'll have to get back to the portal before things get weird."

"Weird, how?" Coulson asked.

"Well, sir...I don't know." Fitz winced and rubbed at the back of his neck. "Seeing as we-we've never done this before, anything could happen. Worst case scenario, this universe-um-it collapses. Best? The Jemma with me right now just...vanishes." He looked up at her and frowned.

She frowned back before looking briefly away. It didn't feel much like an avoidance tactic, as it had earlier, but more like someone coming to terms with their own mortality.

"Either way," Fitz concluded, "you'll probably want to, to send Bobbi through once we've got younger Jemma here. So we can get back as soon as possible."

"Got it," Skye said. "She's prepped and ready to go as soon as Mack can open the portal back up."

"About all that…" Jemma said, taking a step forward. Her eyes were determined again. "I-I want you to take me with you."

Fitz's jaw dropped slightly. "What?" he sputtered, feeling betrayed. "You agreed-"

"I did, I know. I still am." She clenched her fists, as if preparing for a fight. "But if we're able to bring younger me over, and I'm still here...I want to come with you both. I meant it when I said I didn't want to die."

"Can she even do that?" Skye wondered aloud as Fitz shook his head, his mind racing.

"Jemma, I...I don't even know if this will work. The-the paradox might not hold." He didn't want to get her hopes up. "And then there would be two of you back home. Permanently."

She nodded. "I know. That way, we both would get to live. But I wouldn't stay and complicate things. I'd-leave, maybe do some traveling. Younger me could stay with S.H.I.E.L.D. and have the life she was meant to have." When Fitz still didn't look convinced, her eyes turned pleading. "You could try, at least."

Finally, Fitz nodded. "I can try," he confirmed. "But-um-like I said...it might not work."

"All I ask is that you try," Jemma said.

He nodded again, then took a deep breath. "Right. Coulson-sir-I think we're ready." There was really nothing else left to do.

"Copy that," Coulson said briskly. "Skye, how are things on your end?"

It was a few seconds before she replied. "We're good to go, AC," she said. "Mack's got the portal ready to open and Bobbi's set too. Your move, Fitz."

He raised an eyebrow at Jemma. "Ready?" he asked. He expected her to nod, but instead she hesitated. He frowned. "Jemma?"

She looked like she was wrestling with a decision. She took a step toward him, stopped, then finished crossing the distance between them. "Fitz," she said, and she sounded unsure. "If this doesn't work…"

"It will," he said, more confidently than he actually felt. He wasn't sure where her sudden nerves had sprung from, but he wanted to reassure her.

"But if it doesn't." Jemma shook her head slightly before swallowing. Then, in one swift move, she pulled his glasses from his face and moved in close to press her lips to his.

Fitz flinched in shock. It was hard, rushed, almost desperate, and before he had time to even think about kissing her back, it was over. Jemma stepped away and wordlessly handed him his glasses before going back to where she'd been standing before.

"What just happened?" Skye demanded over the comm, her voice shrill.

"Uh," Fitz began, fumbling to get his glasses back on, but Jemma cut over him.

"Nothing," she said, and she was back to the brisk efficiency that seemed to be her norm. "I'm ready now."

Fitz stared at her with furrowed brows, lips tingling, but she wouldn't look back at him. After a brief pause he shook his head as if to clear it. He couldn't focus on what she had just done, no matter how much he wanted to demand answers. "Right. Um." He held the screen up so he could see younger Jemma. "What about you?"

"I'm ready," she said. She still looked anxious. "And I'm standing by the door. Just thought you should know-so I don't land on top of anything."

Older Jemma nodded in understanding and moved a few steps toward the cot. "I'm out of the way."

"Good." Fitz took another deep breath. "Well-here...here we go."

Taking one last look at younger Jemma, he set the screen down on top of the generator and bent to pick up the cables he'd plugged into the power source. Sorting them in his hand, he took one and plugged it into the side of the tracker. The generator immediately began to whine, and it only got worse as he finished plugging the cables into both the tracker and the screen.

"Right!" he said, shouting to be heard over the increased noise. "Jemma, both of you-think of your shared memory, your thought. Remember, it has to-to be the most important thought you've ever had!"

"Shared memory," older Jemma repeated. "Okay, I've got it."

"Concentrate-as hard as you can!" Fitz looked over at Jemma. She'd closed her eyes and her mouth was moving, but he couldn't hear her over the whirring of the generator. It looked like she was repeating a phrase, over and over.

A burst of sparks spit out from the inside of the console as the generator started to vibrate. Fitz jumped back, trying to avoid getting his jeans singed, and cursed under his breath. He kept looking back to the empty space by the door, but nothing was there yet. After another shower of sparks and some worrisome noises from the generator, he picked up the screen and moved behind it so could look for younger Jemma. It was fritzing wildly; she was barely visible, standing still near the door. He clenched his jaw, silently willing everything to work.

Then something appeared in front of him, like an expanding cloud of mist coalescing into something solid and real. It was younger Jemma, mirroring her older self's stance, mouthing words to herself.

"It's working!" Skye yelled over the comm, just as the generator sparked again and began rattling hard enough to shake the entire building. Fitz grimaced and dropped the screen on top of the generator again, gripping the corner of it with both hands in an effort to stay standing. Near the cot, older Jemma had spread her arms and feet out for balance, still repeating her chosen words to herself.

"Come on, come on, hold together," Fitz muttered, bracing for the worst.

Younger Jemma blinked in and out of sight several heart-stopping times before finally coming into focus, her body casting a shadow on the floor from the light of the lamps. Behind Fitz, the generator gave one final, violent shudder before cutting out in the largest display of sparks and smoke yet, forcing him to jump away from it again. The screen distorted sharply before the glass cracked and the tracker split down the middle.

And then there was silence. Fitz froze, not daring to breathe until he was sure it was over. He looked at the generator, which was still smoking and sparking quietly, before looking at older Jemma. She was holding still the same way he was, staring at him with wide-eyed wariness. Then he slid his eyes over to younger Jemma.

She was staring at him too, but her gaze was hopeful, along with something else he couldn't quite identify. When their eyes met, she let out a breath that was more like a quiet, incredulous laugh. He felt something in him relax, and he smiled back at her. It worked.

Then she gave a small cry and launched herself forward to throw her arms around his neck. He staggered back a step in surprise before his arms automatically went around her in return, and he allowed himself a moment to revel in it, in her. Face buried in her shoulder, arms as tight as they could go, breathing in her scent and her warmth and her everything, searing the feeling of her in his arms into his memory. For a moment, they weren't broken. They were perfect.

The sound of someone clearing their throat broke them apart. Jemma pulled away from him, ducking her head a bit, and turned to look behind her. Her older self was watching them carefully, looking a little uneasy. Fitz looked between the two of them for a moment before coughing quietly.

"Right. So," he said, gesturing toward older Jemma, "this is...you, and...you. Yeah."

Younger Jemma took a few steps toward her older self, both of them looking the other over as if sizing them up. "This is so weird," Skye muttered, just as both Jemmas said, "Wow."

"Okay, so it worked," Coulson said, attempting to steer them all back on track. "What's your status?"

Fitz raised his eyebrows as he looked around the room. "I think we're good, sir," he replied. "Nothing seems to be exploding or-or collapsing. But I don't think we need to waste any time. Skye, how soon can you get the, um, the portal open?"

"Mack's firing it up right now," she said, and no sooner were the words out of her mouth did he hear the sound of the console revving up. After it pinged, she added, "Sending Bobbi through."

After a moment there was a crackle of static over his comm, and then Bobbi's voice was in his ear, calm and confident. "I'm here."

"Bobbi's here," Fitz said to the two Jemmas, who both nodded as he bent down to pick his backpack up and slide his arms through the straps. "Bobbi-go through the room after the one you're in right now, and then-then there will be a long hallway. You want the door at the end. That-that's the one you need to keep open for us."

"Got it." He could tell from the way she was breathing that Bobbi was moving quickly.

Older Jemma came to stand next to him-younger Jemma, he noticed, had flattened herself against the wall as her older self went past, obviously not wanting to risk touching her counterpart lest she spark a dimension collapse. "We'll probably run into some robots," older Jemma said. "They first appeared for me when I went through that door, and I saw them turn up as soon as Fitz went through it too. I'm willing it will be the same for Bobbi-so we should be prepared. Did she catch all that?"

"Yes," Bobbi said. "I heard her."

Fitz nodded, trying to catch older Jemma's eyes-he was still full of questions about that kiss-but she still wouldn't quite look at him. "Yeah, she-she got it."

She smiled grimly and opened the door before unclipping her sword and thumbing the power button. "I'll lead the way. You-" She paused as she looked at her younger self, still unsure how to address her. "You stick with Fitz."

Younger Jemma nodded, licking her lips nervously as she looked at him. Fitz smiled at her reassuringly and almost held out his hand for her to take, but instead let it hover at the small of her back as he let her go out the door ahead of him. Then they were jogging across the grass under an early evening sky, the crackling light of Jemma's sword casting eerie shadows all around them. Fitz stayed alert as they ran, listening for any tell-tale pops, and was surprised when they made it back to the main building without trouble.

They raced through the antechamber and into the main circular room. Fitz had just enough time to see Bobbi, bracing her weight against the open door, staves in one hand-he had never been more glad to see her-before four robots materialized in front of them with a flash of blue light, two to each side of the central kiosk.

Older Jemma skidded to a halt, sword raised; Fitz managed to catch younger Jemma by the shoulders and pull her back against him before she could slam into her older self.

"Candidates have been located."

"I'll take out the one on the outside left," older Jemma said, low and fast. "Run through the gap and get to the door; then I'll worry about the others."

"Candidates will now be scanned."

"Are you sure?" younger Jemma asked, her body tensed like a coil ready to spring. Across the room, Bobbi was looking between the two sets of robots, her mouth pressed down into a thin line.

"Positive," older Jemma said, and ran at the robot she'd indicated. When she was within striking distance, she spun in a quick circle, both her sword and her staff flying in a one-two slashing combination. The robot's head fell off mid-scan, severed cleanly at the neck; then the body toppled to the ground. "Go!" she yelled back at them, already turning to the next robot. Now that one of their number was down, their guns were sliding out from behind their faceplates, all pleasantries forgotten.

Fitz pushed younger Jemma ahead of him, and they both ran for Bobbi and the door, jumping over the remains of the first robot as they went. When they squeezed past Bobbi into the hallway, she held up a hand for them to wait. She looked like she wanted to go take care of the other two robots, but older Jemma was already on it, charging across the room to lay into both of them at the same time in a flurry of spins and thrusts. Crouched down next to him, younger Jemma watched in awe. Bobbi looked impressed.

"Her form's a bit choppy," she said, "but I like it. She's good."

"Yeah, because she's a total badass," Skye said over the comm. "I want to shake her hand."

Fitz snuck a look at the Jemma next to him. She was still watching her older self in fascination, and he could practically see the gears turning in her head as she took stock of all the new abilities she'd picked up. Then, as if feeling his eyes on her, she turned her head slightly to look back at him, and gave him a hesitant smile. It only widened when he smiled back at her, and he felt his heart skip in his chest.

Older Jemma moved quickly to join them once all the robots were down, and took the weight of the door as Bobbi straightened to move deeper into the hallway past Fitz and younger Jemma. The door closed behind them, and Fitz breathed a sigh of relief. The hard part-getting through the door-was over. They wouldn't have any problems reaching the portal.

Or not--as they all turned to face down the hallway, four more robots appeared, their guns already locked and loaded. Bobbi's fingers flexed around her staves.

"I'll take point," she said grimly, and started toward them.

Fitz looked back at older Jemma. "I'll cover your backs," she said. "Follow her and stay close, but be careful. They're ready to shoot." She raised her sword. "Okay-go."

Like he had before, Fitz pushed younger Jemma ahead of him, but once they were both up and moving he kept pace with her, their shoulders bumping. Ahead of them, Bobbi had just reached the first robot.

"Candidates will be termi-"

She jammed one of her staves directly into the base of the gun, dodging to the side as it discharged a shot. Fitz and Jemma stopped and quickly pressed against the wall as it blasted a tiny crater in the floor at their feet, then ducked as another robot sent a second shot aimed at their heads. Bobbi bounced back and kicked the lead robot square in the center of the chest, knocking it over. Fitz took the opportunity to move forward, pulling Jemma with him. They crossed to the opposite side of the hall; a glance back showed older Jemma several paces behind them, walking slowly and on high alert. Then there was sudden burst of popping noises, and when he looked back again, Jemma was turning to face the four robots that had just appeared behind her. Up ahead, three more joined the robots that Bobbi was fighting.

Beside him, younger Jemma's eyes were wide. "Why are there so many?" she shouted, her fingers digging into his arm. "There were never this many at once when I first ran into them!"

"They might know we're escaping," older Jemma yelled back, swinging her sword. "We weren't supposed to get through the door!"

From there, it was chaos. Bobbi and older Jemma were both in constant motion, expertly dodging energy blasts while hacking and slashing at every new robot that appeared. Fitz and younger Jemma moved down the hallway in fits and spurts, ducking and pulling each other out of harm's way, never once letting go of the other. By the time they finally reached the door to the first portal room, the hallway was littered with broken robots, a faint haze of smoke in the air, thick with the smell of ozone. Bobbi paused to make sure older Jemma had her remaining robots well in hand before turning and running ahead to check the last room. Fitz and younger Jemma followed.

Through the doorway, he could see the portal. It was open, and he could just make out Skye and May standing on the other side. Behind them, the rest of the cave room faded into darkness. His heart sped up. This was it-he could see the end. It was a straight shot to the portal. They were going to make it.

Just as Jemma ran through the door, Fitz hot on her heels, a robot suddenly teleported in between her and Bobbi. She shrieked and tried to stop and pull up short, but it was too late. The robot had its hand raised and Jemma got a face full of it, the anaesthetic in its fleshy skin knocking her out instantly. She collapsed like a marionette with its strings cut.

Fitz barely had any time to react. He only just managed to catch her around the waist before her weight brought him to his knees; then he was shifting her in his arms so he could see her face, muttering "no, no, no" in a panic as Bobbi bodyslammed the robot above them. Behind him, he could hear footsteps entering the room followed by three more popping sounds.

"Fitz!" He jerked his head up. Bobbi was jamming both of her staves into the face of the robot she'd just shoved away. "Take her and run! I'll cover you!"

He glanced back at older Jemma-she was fighting the three robots that had just appeared-before moving to slide his arms around younger Jemma's shoulders and beneath her knees, picking her up and struggling to his feet. He ignored the way her head lolled against his shoulder, ignored the way her arm hung limply. He ignored how small and slight she felt in his arms, how sick to his stomach he felt. He just nodded at Bobbi and started running.

The room seemed to stretch out before him. He was aware of Bobbi running alongside him, energy beams flying past on either side of them, but he kept his eyes trained firmly on the portal, trusting her to handle any more threats that came their way. His mind was consumed with just one thought: get Jemma to safety. If he failed at this, failed her, what good was he?

Bobbi stopped right at the side of the portal, but Fitz ran straight through it, not even bothering to slow down. Like it had when he passed through before, his body erupted into a storm of tingles. The sensation nearly caused him to stumble and drop Jemma, but Skye and Hunter were standing ready to catch him, and together they got him away from the portal so he could lay Jemma down on the ground. His hands immediately started fluttering over her, unsure of what to do. His eyes were fixed on her face, staring at the bruises that contrasted sharply with her pale skin.

Skye had put two fingers to the pulse point on Jemma's neck. "She's fine, Fitz, she's here," she said in a rush, grabbing his shoulder with her free hand. "She's fine. You did it."

He let out a breath, his heart pounding. He could hear Bobbi and Coulson talking over the comm; a second later there was a rush of noise, and then Bobbi was speaking right behind him.

"I'm back, Coulson," she said, out of breath. "Other Simmons is right behind me, she's on her way now-"

The console blared a loud alarm, one they hadn't heard before. Everyone in the cave jumped and turned to look. Older Jemma had just entered the portal room and, seeing that the coast was clear, had tossed her weapons aside and was running for the portal.

"What's is that, what's happening?" Skye cried.

Fitz watched Jemma run. Come on, he thought, even as the alarm intensified. You can make it.

Suddenly, without warning, May reached over and slammed her hand down on a row of console buttons. The portal's glow immediately changed from blue to red and the alarm quieted, but didn't stop completely. Jemma stopped just in front of the portal and jumped back as if she had been shocked-just like she had hours ago for him, but years for her.

An entirely different kind of shock was running through Fitz. "What the hell are you doing?" he shouted, just as Skye yelled, "May?!"

On the other side of the portal, Jemma was yelling too. "May! Let me through!"

May's face was hard. "I can't let her come through."

Fitz stood up and took two steps toward her, his fists clenched. "Yes, you can! Just-just open it back up, let her through."

"Fitz! Fix the portal, let me through! Fitz!"

May shook her head, and there was something like horrible regret in her eyes. "I can't. You know I can't."

"You can." He could feel his eyes stinging, could feel that tell-tale tickle in his nose that meant tears were coming. He took another step forward, trying to get to the console, but May-whose hand was still covering the buttons she'd pushed-moved to block him with her body. "Why are you doing this?"

"Fitz! Please, you promised!"

May shook her head again, keeping her eyes locked on his. "You said it yourself, Fitz," she said. "The paradox won't hold. There was never supposed to be more than one Simmons and somehow, the portal knows it. The technology must have scanned or registered her somehow when you carried the younger Simmons through, and now it's going haywire. We don't know what will happen if she crosses over, but judging by these alarms it can't be good. We can't risk it. It's a danger to the entire team."

"But…" Fitz swallowed thickly and looked over at the portal in despair. Jemma was still standing there, eyes wide, begging to be let through. "She'll die if-if we don't."

"She'll die here, too," May said, but her voice was quieter now, gentler. "Somehow, eventually. We all will. But there can only be one Simmons here. Deep down inside, I think you know that." She paused. "It's up to you to decide which one."

Fitz's eyes widened in horror. "But-I can't…" He looked away from Jemma at the portal, to the Jemma who was still lying unconscious on the cave floor. They were both Jemma, both the woman he loved. It was an impossible choice; he couldn't pick. Either one would feel like a betrayal. He felt himself go numb as panic and desperation rose within him again, making him feel light-headed and nauseous. He couldn't pick. He couldn't. Helpless, he looked up. Mack was standing next to the console, his eyes filled with nothing but sympathy. Bobbi and Hunter were kneeling next to Jemma on the ground, and for once there was nothing sullen or sarcastic about the other man's expression. Next to them stood Skye, looking just as heartbroken as he felt.

"You completed your mission," Coulson said in his ear. His voice was low and solemn. "You brought Simmons back. The other Simmons…" He fell silent for a moment. "Let her go, Fitz."

There was no use in pretending he wasn't crying, now. His vision blurry with tears, he bowed his head and turned away from everyone, trying to hold on to at least a scrap of his dignity.

"Fitz."

It was older Jemma again, but she was no longer begging. The fight had gone out of her voice. When he looked up at her, she was standing very still, her hands hanging loosely at her sides. "Fitz...come here. Please."

He hesitated, but when May nodded at him he moved until he was standing just across the portal from her, as close as he dared, just like he had the last time. She was watching him closely, tears on her face.

"I'm sorry," he choked out, before she could say anything. "I'm sorry. The-the paradox, it won't-I can't-"

"I know," Jemma said quietly, swallowing. "And-I know I said I didn't want to die, and I meant it. But...I think this is probably for the best." She attempted to smile, but it was small and strained.

Fitz felt his stomach lurch, and the tears finally spilled over. "Don't-don't say that," he whispered. "You're still Jemma, and I, I don't-I don't want-"

She smiled again, and this time it looked brave. "Fitz, please." She reached a hand out as if she meant to touch his face, but dropped it. She couldn't reach him. "If it had been me, I think-it might have been difficult. But this way, it's a second chance. For both her and for you." At his questioning look, she tilted her head. "She still needs you, Fitz. Don't think for one second that she ever stopped."

Oh, how he wanted to believe her. Fitz knew he could trust this Jemma, because she had let down her own carefully-constructed walls for him, but it was hard. Nothing could fill all the months of silence that existed between them, and nothing could erase the pain he still keenly felt whenever he thought about how she had left him. It still felt insurmountable. But if she believed there was still hope, he could believe too. He could try.

"I'm sorry," he said again, and swiped at the tears on his cheeks. He didn't know what else he could say. "I wish there was another way."

"I wish there was, too," Jemma said. "But you'll be okay. And so will I." She looked briefly down then, taking a deep breath, and when she looked back up, her eyes were bright. "Fitz, I…"

He looked back at her, his breath caught in his throat. But after a moment, she just sighed. "Thank you," she said. "Thank you for giving me hope when I had none."

Fitz's heart thudded to a halt in his chest. Jemma smiled at him again, then looked to the side as three robots appeared in the room behind her. She nodded slightly to herself, then gave him one last smile before turning to face the robots, her shoulders squared and her chin high. They were already walking toward her, guns visibly charging.

He backed away from the portal a few steps, feeling sick. "Close the portal," he said hoarsely. "I-I can't watch this."

Mack said something, too quiet for him to hear, and May murmured, "Do it."

Fitz was certain that his last look at the older Jemma-brave and defiant and incredible, right to the very end-would stay with him until the day he died.

The portal blinked out and the silence that followed felt like it would crush him.