He was squinting. Partially it was because the creepy underground alien city was dark, and his hyped-up glow stick wasn't accomplishing much. Partially it was because his heavy breathing was fogging up the inside of his hazmat suit's helmet. Mostly it was because his brain hurt.

Of course, his brain hadn't stopped hurting for a while now. But certain things made it worse. Things like the others glancing all concerned-like at him when they thought he wouldn't notice. Things like simple equations he could solve in his sleep getting hopelessly jumbled up when he was awake. Things like words getting stuck between his brain and his mouth. Things like alien cities and weird writing and almost shooting alien-possessed Mack. And things like Jemma. Mostly Jemma.

He shook his head and kept walking, glancing from the carved floors to the map in his hand.

"Alright, just another right up here and two more lefts…or is that a right?"

He muttered out loud, mostly to block out the dialogue playing on repeat in his mind for the past ten minutes since he'd left…

This is taking a little longer than I hoped.

We'll need to move more quickly.

We should split up.

No!

Bad idea.

No, it's a good idea. We're running out of time. I'm familiar with the explosives. I have a map. I'll see you two at the garrison.

Fitz.

Just trust me on this, Jemma. I'm not afraid. I can do it.

Fitz.

Yeah. Other direction.

It was a good idea to split up. Of course it was. They could save time, cover more distance, get out quicker…he could think more clearly…if he could just get her voice out of his head.

Fitz.

It was the way she'd said his name. He understood it. The first time it was worry. Maybe it was just worry that he'd mess up because he couldn't think straight. But no, it was worry for him, for his safety. He knew because he'd heard it before.

Jemma, stop. Stop worrying about me. I can do this.

You'll be careful?

That day she'd handed him his favorite sandwich. She'd spontaneously reached out and grabbed his hand.

Fitz.

The second time she'd said his name was even more familiar. He understood every part of it—the intonation, the multiple meanings: part annoyance, part ironic amusement, mostly exasperation. The way she used to say it on a regular basis.

There had been those brief, flickering moments all day. She finished his sentence—not just the struggling-to-make-up-for-his-brain way, but the old being-on-his-same-wavelength way. They'd come to conclusions together that no one else understood. Coulson had called them Fitzsimmons. In those moments, he'd almost caught a glimpse of who they used to be together. Then she'd smile at him a little, and he could see the pity there, the regret, and his brain would start hurting again.

"You missed your right turn, there."

He didn't jump at her voice, because he was beyond being startled by it. He just closed his eyes momentarily before turning his light on her.

Simmons stood there, hands clasped in front of her. Same blue sweater, white collar, long hair pulled back in a ponytail, expectant smile.

"What on earth are you doing here?" Fitz mumbled, pushing past her to take the right turn.

"Helping you out, obviously. You may be better with explosives but I've always been better with maps."

"I don't need you, alright?" He tried to walk faster, knowing it was pointless. She followed.

"That's a good thing!" she responded cheerfully. "You're making progress!"

"I thought I'd made this progress already. I haven't seen you since—well—since you came back. The real you, I mean."

"But you've been having a harder time thinking since then."

"Yeah, well, that's not exactly my fault, is it?"

"We're here. This is the site for your bomb."

"I knew that…"

Fitz knelt down, feeling Simmons watch over his shoulder but unwilling to look at her. He fiddled with the bomb. Trip's old school tech from his grandpa was cool, but extremely finicky. It would have been hard enough with his hands free, since he still only had one hand that really functioned normally, but the gloves of his suit made it even harder.

"Don't stress out. Just take your time…"

"Shut up, Simmons."

"Well that was certainly uncalled for."

"Just be quiet!" he yelled, punching the hard stone floor. It was his bad hand. And it was a bad decision. "You're not here. You're out there somewhere, hopefully back at the top by now, safe with Trip. You're… Wait… Got it!"

The detonator started ticking immediately. He glanced back at the map to try to find the quickest way back to the garrison.

"Alright, time to get out of here," he said. "This way."

"Oh, so you want me to come along now?" Simmons said, crossing her arms.

"Seriously? You're my subconscious, for pity's sake. Don't act so offended, just come on."

They made their way back through the winding tunnels, following the map. Several minutes passed, but none of the tunnels looked familiar.

"Shouldn't we be getting close by now?" Simmons asked. She never could hide the worry in her voice.

"We're almost there. If we just go a little further-"

"How much time do we have before the bombs…you know…"

"Explode?" Fitz fired over his shoulder at her. "I don't know! I've been trying to keep count in my head but you keep messing it up."

"Oh, I keep messing it up, do I?"

"Yes! If you would leave me alone I could concentrate better."

"Are you sure this is the right way? That turn back there looked familiar. If you could just let me see the map…"

"There's no way I'm letting you see the map! I'm the one in charge here!"

"Well if I'm your subconscious then maybe I know something you're missing."

"I'm not missing anything, ok? I'm fine, just let me think…"

"I'm just trying to help."

"Simmons!" he yelled, wheeling around to face her. "I can't just sit here and argue with you. I need to find you—the real you—so just be quite for a minute!"

He turned to round the next corner…and smacked into someone.

Fitz screamed. Probably more high-pitched than he meant to. Trip yelled out "Hey man!" and gripped Fitz's shoulders to keep him from falling backward. Jemma, standing right behind Trip, had a concerned look on her face.

"Fitz, are you alright?"

Fitz quickly backed out of Trip's hold on his arms. "Yeah, I'm fine, of course. Nothing wrong."

Trip nodded. "We were just headed back to the garrison to get up top, hoped we might find you there, and we, uh, we thought we heard a voice, and then we realized it was you…"

"Yeah, right, just trying to read the map, find my way back too," Fitz stammered quickly.

"You're such a liar."

Fitz bit his lip and looked back over his shoulder, trying to ignore the knot in the pit of his stomach. Simmons was still standing behind him, arms crossed, a slight smirk on her face.

"You weren't reading the map, you were talking to me."

"You can't both be here," Fitz breathed, staring back at her. "You have to leave."

"What was that?" Jemma asked, taking a step toward him. "Fitz, is something wrong?"

He glanced at her. Her short hair was pulled back inside her helmet, but wisps of it curled around her face. She looked confused and upset. He looked back over his shoulder at Simmons. Strands of her long ponytail had fallen over her shoulder. She watched him expectantly.

"We have to, um, to—to leave. We have to leave. That's all I said."

"You got that right," Trip said, glancing nervously at his timer.

Fitz pulled away, leaving both Simmonses behind him, and started down one of the tunnels.

"Fitz, it's this way," Jemma called, pointing down a passage in the opposite direction.

He glanced down at his map. "Ah yeah, of course. Right then, let's get out of here. This place is weirding me out."

Jemma led the way back to the entrance. She occasionally glanced back at Fitz, looking like she wanted to say something, but he avoided eye contact. He refused to glance over his shoulder to see if subconscious-Simmons was following.

When they reached the garrison, Trip and Fitz both insisted that Jemma go up first. She rolled her eyes but obviously knew there was no time to argue. Trip put up more of a fight, but Fitz still made him go first.

For just a moment, Leo Fitz was alone in the alien city. He closed his eyes and sighed.

"You have to leave now," he said softly.

"I know."

He opened his eyes. Simmons was smiling at him, her ponytail moving slightly in a breeze he couldn't feel.

"That's because you have to let me go," she said gently.

"I thought I just got you back."

"You got her back. I'm not her anymore. She's different now. Just like you are."

"Does that mean…" He paused. "It means we can't go back, doesn't it?"

She took a step closer. "It means you can go forward."

The harness came whirling down, and he heard Trip's faint voice yelling down at him to hook in. Simmons smiled, reaching out and placing her hand on his shoulder. Out of habit, he put his hand over it.

"You're almost there," she whispered. She backed up, and Fitz hooked into the harness.

"Fitz?"

"Yeah?"

"Never stop fighting, and never give up on me."

"Ok… Wait." He stopped fiddling with the harness and looked at her one last time. "Do you mean 'me' as in Jemma, or 'me' as in…me?"

She smiled—that wrinkled-nose, lips-pressed-together smile of hers, and she nodded. Then she was gone, and the harness was humming as he was pulled up out of the alien city.

He yanked off his helmet as soon as he reached the top and breathed in deeply. Jemma let out a relieved sigh when he made it up.

"Ten minutes to spare," she declared triumphantly.

Either hearing the actual countdown or simply being out of the eerie city sent a wave of reality crashing over Fitz, along with a stab of guilt as he remembered the friend he left behind.

"Yeah. I'd be much more exited if Mack wasn't still down there," he said, realizing that there was no way they would get him out now.

"I can't think about it, it's too sad," Jemma answered.

Trip's phone was ringing, so he put it on speaker. "We're out," he answered without hesitation. "It's all good."

May's voice crackled on the other end. "Raina escaped into the tunnels with the obelisk."

"I wouldn't lose any sleep," Trip responded. "The place is about to blow in less than-"

"Skye and Coulson went in after her."

Fitz knew all too well how it felt to be without oxygen. Suddenly that familiar feeling was taking over his body again. There was no more air in the room. He couldn't breathe.

Jemma's voice broke through the fog. "Trip, you can't go down there!"

Finally processing what Trip was doing, the only word that Fitz could push out was "no," over and over. But Trip didn't even acknowledge them, just frantically grabbed his gear and hooked into the harness.

"Trip, it's too dangerous."

"Trip, there's not enough- Trip!"

"No!"

Fitz and Simmons screamed after him, but Trip had already disappeared down into the city.

Jemma dropped to the floor beside the hole. Fitz grabbed his hair with both hands, feeling like he was on the verge of hyperventilating. In the past when he felt panicked, his brain would move at a million miles an hour, trying to think through every detail at once. Now his brain was entirely, terrifyingly blank. He couldn't focus on anything, couldn't form a complete thought. The only thing that existed was his panic.

"We have to—to do something, there has to be something—to help—anything." He started pacing, trying to force words past the pain in his head. "We can't just—with them down there—maybe if we could—"

"Fitz!" Jemma squeezed her eyes shut and a tear rolled down her cheek. "It's no use."

"But Trip—"

"He went down without a hazmat suit," Jemma said, staring down the hole, her voice thick with emotion. "The city could do the same thing to him as it did to Mack."

"Coulson and Skye…"

"They have less than ten minutes. And even if Trip can get to the explosives…"

"…who knows what the obelisk will do down there," Fitz finished. Apparently the only thoughts that would form fully were negative ones.

Jemma held her head in both hands as a sob escaped her. Fitz took a step toward her, wanting to bend down and hold her, to tell her it would be ok…but it wouldn't be ok, and he didn't know if she would want him to hold her anymore. He wheeled back around, screamed, and punched the stone wall.

"I can't just sit here and do nothing," he said. He took a deep breath, headed to the edge of the hole, and began to hook into the harness again.

"What on earth are you doing?!" Jemma screamed, jumping up to stop him.

"I'm going back down there. They need help."

"You can't!" She grabbed his hands in both of hers.

"I still have my suit on, so it'll be safer for me, and I can go down and help get them out, or—"

"Fitz, there's no more time, and there's nothing you could do to help."

"Don't treat me like I'm useless!" he yelled, yanking his hands out of her grip. "I can do things to help, I've been doing things, and I'm—I'm almost there—I just need to do something."

"That's not what I meant. But I'm not letting you go down there, it's too dangerous."

"I have to."

"Don't you dare do this to me, Fitz!" She screamed, gripping his sleeve. "Don't put me in this position again. Most of the only people I truly love in this world are down there. I could lose all of them today. Don't make me lose you, too!"

She turned her head away, trying to hide her tears, but she wouldn't let go of his sleeve. He stared at her.

"Ok," he whispered shakily. "Ok."

She looked at him and met his eyes, her face stern. "Promise. Don't leave me."

"I won't."

"Take off your suit, then. Take it off so I know you won't go down there."

Fitz took off the jacket of his hazmat suit, his arms feeling heavy, and stepped out of the stiff white pants. Jemma picked them up and threw them across the room, then turned her back to him and took a few steps away, wrapping her arms around herself. He stared at her back in shock, his entire body shaking under the weight of his emotions and his inability to sort them out. Then he realized it wasn't just his body that was shaking.

Jemma wheeled back to him, her face panicked. "What is that?"

The ground under their feet was moving more and more every second. Jemma let out a small scream as some of their equipment toppled to the ground beside her. Fitz immediately crossed over to her to make sure she was alright.

"Is it the bombs?" Jemma yelled over the growing noise.

"I don't think so," Fitz answered. "This is something else."

Suddenly the entire building was shaking. Equipment was falling down on all sides. The air was filled with dust as the ancient stones around them cracked and crumbled.

Fitz ran to Jemma and held her protectively in his arms. For the briefest second her body tensed—then she was holding onto him. His mind flashed back to the last time he'd held her, at the bottom of the ocean, when he thought he'd never hold her again, when she'd kissed him, when he'd finally been able to reveal how he felt, when he'd thought that would be the end.

Here they were, at the end again, the world crashing around them, no idea what was happening or what would happen next—but all that really mattered to him was that she was in his arms again. They were together. And if they made it out, whatever happened, whatever all this was between them, they could work through it. They could fix it, together, like they always did. They could move forward.

Jemma reached up and gripped his shoulder. Instinctively, he reached up and covered her hand with his. But this time it was real.