Tony wakes up on the floor.

To be exact, he's flat out on his stomach, one hand sandwiched between his face and the hardwood and the other stretched out in front of him, reaching with clenched fingers. The dream still floats fresh in his mind. And it was a dream: no point in pretending otherwise, no matter how real it felt. Real enough to half-wake him in the middle of the night. Real enough to coax him out of bed, sleepwalking across the length of the room. Real enough that he can still see the dim silhouette of a tall figure in the doorway, and real enough that he can still hear a low, growling voice echo in his ear.

(Tony Stark...)

He pulls himself up onto his hands and knees, rubbing the tail ends of fog from his eyes and giving his head a shake to clear his brain. "Jarvis, lights," he mutters through a yawn. They come up too bright, glaring suddenly and cutting through the darkness; Tony shields his face with an arm. "Thirty percent!"

"Apologies, sir."

The lights dim to a tolerable level. Tony blinks to adjust his eyes, pushes his hair back, and drops his arm. "Better. What time is it?"

"Three twenty-six in the morning."

"What time did I fall asleep?"

"Nine forty-two."

Five and a half hours of sleep. Well, that's a lot better than what he'd been averaging over the last couple months, so he'll count it as a success. Sort of. Waking up fifteen feet from his bed kind of puts a damper on things, but at least he slept. He actually slept.

The pills Bruce gave him worked.

"Bruce still down in the lab?" he asks, already knowing what the answer will be before Jarvis answers in the affirmative. He can sense the crackling vibrancy of Bruce's energy, active somewhere in the house. Not possible to pinpoint, but present all the same. A trickle of hazy knowledge through the back of his mind.

He yanks on the first pair of pants he grabs from the closet, followed by a shirt selected with equal care, and heads out to find Bruce. It's not hard. All he needs to do is follow the noise: the irritatingly cheerful treble beat of 80s bubble-gum pop grows louder with each step he takes towards the lab. By the time he's down the stairs, he can hear Bruce's voice half humming, half mumbling-singing along.

What are words for... When no one listens any more...

Leaning against the wall at the bottom of the staircase, Tony can't help but smirk. "I think you might be the last person left on Earth still rocking out to Missing Persons."

Bruce freezes mid-head-bob, whipping around with a HYDRA gun energy storage cell in his hands and something between open-mouthed shock and a sheepish grin plastered across his face. "Um," is all he can seem to say for a few seconds while Tony tries not to laugh. Then, "I... thought you were in bed."

"I was in bed. For almost six hours. That's long enough, don't you think? Especially with the party going on down here."

"Six..." Bruce starts, but doesn't even bother finishing that thought, cutting himself off to look at his watch. "Oh. Oh boy. It's three-thirty, isn't it?"

"Yep." Tony, sauntering into the lab, claps him on the back. "Don't worry about it. I lose track of time, too. It's practically a requirement for working in here. You start something just after dinner, and then, bam! Suddenly, three in the morning."

"But did you get any sleep?" asks Bruce in a clever little shift of the conversation.

And that's a good question. Did Tony get any sleep? Technically speaking, the answer would be 'yes'. He did sleep, for a while, thought the bizarrely hyper-realistic dreams and the confusion of waking up on the floor may have counteracted any restful benefits. But still he nods while staring down at the array of gun parts spread out over the worktop and says a quiet, "Yeah," because that's the answer Bruce is looking for. And it's a lot easier than trying to explain the truth.

Bruce nods along with him. "That sounds like a 'yeah, but'."

"Yeah, but," Tony agrees. "Just some crazy dreams."

"Sleepwalking?"

Tony's jaw reflexively clenches. How did he know?

"Common side effect," Bruce explains. "The pills knock you out, but a lot of people experience incredibly vivid, strange dreams, and some end up sleepwalking. A few have a bad reaction and vomit all over themselves, soooo... Good thing you dodged that one?"

"Eh, the night's still young," mutters Tony. "You never know what magic might happen." Glancing down at the worktop again, he sets a white plastic cylinder spinning on its side. "Make any progress?"

"If you count ruling out eight more simulated designs as progress, then yeah. Progress was made. Explosive progress."

Bruce goes through them one by one, having Jarvis bring up the 3D recording of all eight sims for Tony to watch. All eight fizzling failures. Six lasts the longest, with all beams fired up and focused before the casing cracks and a spark ignites, turning the whole display into a ball of flame. Seven causes the smallest explosion. Just a little fire, a puff of smoke, and a broken collapse. Eight doesn't explode at all. But then, it doesn't seem to do anything at all, either. No explosion, no fire, no smoke. No portal.

"What's the deal here?" Tony asks.

"Relay," Bruce answers, and expands the holographic model to show Tony its inner workings. "The big problem is that the energy trapped in these guns is way less stable than the Tesseract itself. Harder to focus and stabilize. This is a lot trickier to manipulate than what Selvig and I had on our hands, so everything he and I did there isn't helping me much here. The storage cells have a lot of output power, but the minute you fire them all together in one beam, the initial energy flare is too much to contain. The casing just can't hold it. It breaks through, and you've got a little bonfire on your hands for the next twenty seconds until the cells deplete and it all sputters out. But if you trigger them in sequence, staggering one through eleven so each one flares as soon as the last has stabilized, it can be contained. That's what you're seeing in number eight. The design doesn't work, but there is one interesting little thing I want to show you."

He fires up the sim again, this time in slow motion, isolating one central beam. "As soon as I saw this, I remembered something Loki said to us all at that meeting back in New York. When he was describing the Tesseract, he said something about it being a 'semi-sentient' power source. I thought it was total crap at the time, but..." At a fraction of its full speed, a single beam from a single HYDRA cell begins to glow and expand. "Check it out. This beam is going to take almost fifteen seconds to stabilize, running the sim at one tenth speed. Watch what happens when the next few kick in. Eyes on the timer."

Just as Bruce promised, Jarvis clocks the first beam's stabilization at 14.7 seconds. Immediately, the next one kicks in, joining the first, though the timer tags its stabilization at 8.1 seconds. The third takes 6.8, the fourth 7.3, the fifth 7.8, the sixth 6.9: on they go, pulsing to life in sequence, all hovering around the seven-second mark. When the last evens out at 7.6, Tony can't help but shake his head in wonder.

"It's like they latch on to each other. The first beam braves the way, and the rest of them just follow in its wake down the path of least resistance, stabilizing in half the time."

Bruce nods. "Yeah, exactly. But weirder still, the energy is drawn to its own kind. I purposefully set these out of alignment on some tests I ran, just to see what would happen, and the beams actually curved their trajectories to join together. Up to almost twenty degrees, which is... extreme, to say the least."

"So why doesn't it work?" asks Tony, maybe stooping to stupid questions, but sometimes things just work out better if he thinks them through out loud. "Everything's aligned. It's all going according to plan. But no portal. The beams even out, and if we start them up in a controlled sequence they don't generate enough of a flare to blow through the casing. Staggering at point-nine seconds actual speed should give each one more than enough time to..."

Oh. Time. Right. That inconvenient little piece of reality knocks his train of thought off track before he can even finish the sentence. "It times out," he says instead, looking for confirmation of what he already knows to be true as he frowns at Bruce. Bruce nods while staring down at the computerized display. Shit. "We can't afford to waste that much time starting up the beam when the cells have only twenty seconds of continuous power in them in the first place. If we need a set window to grow the portal, and another for safe shutdown, we need to cut-"

"Minimum three seconds off the start-up," Bruce answers for him. "Though I'd feel safer with three and a half. So like I said... this is a neat observation, but it's still not where we need to be."

Maybe not, but they're close, and the feeling in Tony's gut says this new development will take them the rest of the way there. He's just missing something. One little tweak.

Squeezing his eyes shut, he rubs his hands over his face and presses his fingertips into his eyes. His skin feels sweaty and slick, and his head is still all wound up and off kilter. He needs coffee. And a shower. And more coffee. In that order.

"How about this," he says, looking up in time to catch Bruce trying to fend off a yawn. "I'll take over the night shift for a while. This gives me a lot to work with. See if I can come up with any way to cut down on the time. Play around with a few things. You catch a couple hours sleep, and we'll reconvene later."

"I'm not-" Bruce begins, but another yawn that he can't quite stifle in time slips out. And his shoulders sag in an admission of defeat. "Okay, now that I know what time it is, I'm exhausted. This is your fault. You shouldn't have told me. I'm going to bed, but I'll set my alarm for nine. Don't solve all the problems before I get back."

"I'll try not to," Tony answers with a wry smile, or at least part of one. Solve all the problems? Not likely. Not yet. Not with the way his head feels. And absolutely not with the sense of disappointment hanging heavily inside that he's still coming up just short of one crucial breakthrough.

ooo

Coffee. Then shower. But first coffee. Tony lasts a whole twenty minutes after Bruce's departure, which is twenty minutes of staring at screens and tech prints and 3D renderings. All of it makes his brain ache. Coffee. Yeah. Necessary. So he trudges up the stairs and into the kitchen and plants himself, elbows down, on the counter in front of the ridiculously complicated machine Pepper bought earlier in the year. One of those home barista piece of shit things that can make coffee every possible way under the sun except the way he likes it: plain swill, in a large pot, for ease of drinking five cups in quick succession.

One perfectly crafted cup at a time will have to do. He shoves his mug under the spout and watches as the thin trickle of dark brown liquid slowly pisses its way out, joined, once the mug is partially full, by an equally unappetizing dribble of milk half an inch to the side. It swirls and blooms in a cloud of creamy beige, expanding from middle to rim to fill the entire mug.

Like the elusive space portal, Tony thinks. Growing from the beam of milk. How easy would life be if I could make a milk portal in a coffee mug? Though it probably wouldn't work because the pissing coffee and milk beams don't even line up. But... if they had the same properties as the Tesseract energy and one curved to meet the other...

After that thought, seconds pass before he remembers to breathe again.

"Holy fuck."

He almost skids out as he takes a corner too fast, grabbing the edge of the wall to catch his balance as he charges down the hallway to Bruce's room. A more courteous person might knock before throwing the door open. But in Tony's experience, courtesy and major scientific breakthroughs generally don't go hand in hand.

"Bruce!" is all he can say once he's standing in the doorway of the darkened room. "Get up!"

Bruce fumbles for his glasses on the nightstand as he sits up. Then looks at the clock. "Tony... I haven't even been in bed for ten minutes. What did you do?!"

"The beams! Pepper's stupid coffee machine showed me!"

That explanation does nothing to alleviate Bruce's confusion. "...What?"

"They don't have to be in one casing! If you're right and the energy is attracted to itself, the beams will synchronize even if triggered from different points! As long as they're aimed at the same place!"

"You mean..."

"We've been stuck on trying to reconfigure Selvig's single-beam design, but what if we had eleven beams? I wrote this idea off at the get-go because I couldn't think of a way to bend the outputs into one merged line, but now that you've figured out they do that on their own... Eleven different casing! All beams converging into one before the portal initiation point! With eleven casings there's no need for a relay, and no containment danger with the initial energy flare!"

The expression of uncertainty doesn't even have time to fall from Bruce's face before he throws the covers back and jumps out of bed. "Oh my god."

"Jarvis!" Tony shouts, and he's already sprinting again back down the hallway with Bruce as close as a shadow on his heels. "Start a new project file! I want each energy cell in its own casing. Same device, same design, but replicate and decrease size for a single cell. Honeycomb layout. Focus all of them on a singular point, distance forty meters. How soon can we get a sim?"

"Rendering simulation now, sir," Jarvis calmly replies.

He takes the first four stairs to the workshop two at a time, which turns out to be a terrible idea when he almost loses his footing and risks crashing the rest of the way in a painful heap of dislocated limbs. He forces himself to slow down. One step at a time. Just one at a time. He's waited three months for this moment. He can wait another three seconds.

"Render complete," Jarvis announces as Tony jumps from the second-last step. "Running new simulation."

It looks like some kind of sci-fi cannon rising up in the holographic display: three rows of gun-barrel beamline casing units, one on top of the next, all aimed at a single pinprick of light a foot away at the far end of the display. As soon as Tony and Bruce reach the table, the new design sim begins to glow with energy.

And promptly explodes.

"Son of a..." Tony swears, cutting off the last word with a hard bite to his lip while Bruce responds with a dejected, though more polite, "Aww."

"I really thought that would work."

"So did I," says Bruce.

And so it will work. It has to work. If two smart guys say it's going to work? It's going to work. They just need to figure out how. An adjustment here. A realignment there. Tony prods the smouldering holographic debris with the end of a pen, watching digital smoke rise from the worktop.

"Okay," he says after a seconds-long pause. "This is the same problem we had before, right? It explodes. Too big of an energy flare at start-up. Maybe... the tight honeycomb pattern won't work. Maybe the initial flare is strong enough to break through the casing when in close proximity to others. The energy's trying to converge too soon and expands outward rather than in the intended beam. Jarvis? Revamp the layout. This time leave a minimum four hundred millimeters of space between each casing."

"Rendering new simulation now."

"You think that'll help?" Bruce asks, sounding sadly unconvinced after the last spectacular failure.

"Of course," Tony answers. "Yes. It will definitely, absolutely, beyond a doubt work this time."

He nods once to himself, that kind of purposeful, determined nod, when the new spiderweb of a design floats into being in front of him.

"Jarvis, trigger the centermost beam first. Once it's stabilized, send in the rest."

At Tony's side, Bruce quietly murmurs, "Fingers crossed."

Fingers, yes. Toes? Those too. Hell, if it would help this crazy mission succeed, Tony would willingly cross every available part of his body. But he settles for clenching his hands into fists as the central beam on the newest sim fires up like a lightsaber and shoots across the display. The other ten follow two seconds later.

At the end of the worktop, a miniature cloud of energy begins to grow. And solidify.

And the tiny holograph of a portal flickers to life.

ooo

"So you really want to go through with it."

Tony swirls his orange juice glass before speaking, watching pulpy liquid fingers slosh up the sides. "Yep."

Bruce's eloquent reaction to that is nothing more than a grunted, "Huh."

This is how they celebrate success: by sitting at the dining room table with a tray of OJ and Cheetos. The biggest scientific breakthrough since electricity waits right downstairs, and they're marking the momentous occasion with light snacks. There was elation, at one point. And there still is, on Tony's part. Bruce, though... Bruce stares down at his hands like he's in a trance, occasionally swallowing a yawn. For him, the rush of excitement has passed. Now he's back to where he was on the phone on Halloween. The same uncertain hesitancy creeps through his voice when he speaks.

"I only think..." he tries again.

"You think now that we've actually solved the problem of wormhole space travel we should stop here in the design phase?" Tony asks. "You don't want to move forward and watch this puppy in action?"

Careful. Bruce is too careful in his answer, handpicking words and forming them slowly, like they're nitroglycerine in his mouth. "No. I mean... Yes, I do want to see it in action. Of course I do. Eventually. I just... I think maybe, before you do anything big like trying to teleport yourself across the galaxy, you should... Tony, you should step back and think, really think, about why you're doing it."

"Because I want to go to Asgard. Isn't that a good enough reason?"

"But why do you want to go to Asgard?"

"Who wouldn't?"

"Tony..." Bruce groans.

"Bruce..." Tony returns.

"If this is just about Loki..."

With a frustrated grunt, Tony slams his glass down on the table. "Okay. It's about Loki. Is that what you want to hear? I admit it: I'm risking my life and rewriting the laws of physics for some guy I screwed, like, twenty times."

"You said you were only with him for nine days."

"Okay, so thirty times then. Whatever. The point is, I want to go to Asgard. And if Loki makes up ninety percent of the reason I have for going – the other ten percent being legitimate scientific curiosity, but let's not lie, it's mostly Loki – well... that's my problem. If I die in the process, it's my problem. If I miscalculate the portal and end up being sucked into a black hole, also my problem. But if give up now that I have this chance right in front of me, I'll regret it for the rest of my life. And that'll be an even bigger problem. He's really good at sex, Bruce."

Bruce groans. Full-out, drop-the-head-in-the-hands groans.

"I mean amazingly good."

"I don't want to know."

"My memory's a bit foggy but there's a high probability I accidentally told him I love him."

"Tony..."

"More than once."

"Tony."

"FYI, never sleep with a space wizard. It'll ruin your life."

"Okay, stop," Bruce snaps. "You're joking and being a smartass when-"

"You're surprised at this because?"

"-when I'm trying to bring up a real concern. I asked you why you wanted to go to Asgard because to me... you're acting kind of..." He doesn't say what. Just sighs. "You're sleeping badly, overtired, and, by your own admission, suffering from a mental..." He doesn't say 'breakdown', either. "You're not yourself. And I'm honestly worried you're doing this because that scepter Loki left behind is having some kind of negative effect on you."

"No."

That answer, that one word, comes out a lot louder than Tony means it to, and he winces at its blunt force as Bruce flinches away from him. "Sorry. But no. It's not." It's really not. Really. Not. "This has nothing to do with the scepter, and you know how I know that? Because I'd do the same thing if it were Pepper instead of Loki. If Pepper somehow ended up across the universe and I had a chance to find her? You damn well bet I'd try. If it were Rhodey? Or, for that matter, you? Or Steve? Or, hell, even Coulson or Natasha, because I'd probably feel bad and guilty even over them and want to set things right? I'd do it. You think I wouldn't do it?"

"No..." Bruce mutters, though that careful tone has shrouded his voice again.

"I know you don't like Loki," says Tony. "And I don't really expect you to because he's an evil fucking asshole, but if you knew him you'd know... um... that's just one of many equally horrible facets of his personality. But luckily, this isn't about you or what you think. It's about me and somebody I care about for reasons that... who knows. He's not always evil. Just occasionally. We spent a lot of time in Phoenix with him not being evil. It's different when it's just the two of us and maybe for a second we can both drop all the crazy bullshit we always carry around on our shoulders and..."

It's so hard, trying to explain these simple things. Thoughts that make so much sense in his head are impossible to articulate with Bruce's raised eyebrow staring him in the face like that, judging every poorly formed syllable that comes out of his mouth. Every weak argument.

"I'm going to Asgard, Bruce. If you don't like the idea of me doing this for Loki, then tell yourself it's for some nameless friend, or for pure science, and maybe that'll make it acceptable. But I'm going. It's the right thing to do, and I know that, because the only time my conscience is at peace is when I'm working towards that goal. I have to go. Maybe you can at least understand that I need to go. It's a compulsion pushing me from inside and it won't let me stop. I can't stop, and can't give up, because the second I do I start to panic, thinking, what if I'm the only person who can do this? What if I'm the only one, and I give up, and then I've failed?"

"Okay," says Bruce, quiet and slow. He stands up as he speaks. Sets his glass back on the tray and sweeps aside a scattered mess of cheese crumbs from the table. Moments of stalling like he's working up courage before he opens his mouth again. "You know this is your own choice and I won't stand in the way. I promised to help, and I will, until the end. But just..." He lifts his hands, fingers picking nervously at one thumbnail. "Just promise me, in return, you'll think it through for at least two days before we go any further. Because the way you're talking? You need to go? A compulsion pushing you forward? You can't give up? I want to make sure it's really you making this decision, and not something or somebody else making it for you."

Maybe the anger that ignites in Tony is irrational, but really, when you think about it, how often is anger really rational? Justified, sure, but rational? The feeling starts in the back of his neck, hot and tingling and a little like shame, before it seeps down through his bloodstream to invade his whole body. Makes his fists tighten. Makes his teeth clench. "And that's what you really think?" he asks. "That I'm... possessed or something?!"

"I didn't say that. But..."

But the implication is pretty damn clear, and it only stokes Tony's anger. "But obviously, no matter what I say and how I try to explain myself, none of my reasons will ever be good enough to convince you I'm not crazy and this is really, one hundred percent, what I want to do?!"

Bruce's voice is so calm despite the fidgeting of his hands. "I'm only trying to make sure. Before you go ahead with this, I only want to be sure that you're doing it for the right reasons, and you've thought about all the risks, and you're confident beyond even the tiniest doubt that it's the right choice. I just don't want to see any emotions or misplaced eagerness affecting your judgement, which is why I think we should wait on this a couple days at the very least. Things don't always end well when you're too quick to make yourself the test subject of unknown technology. Ask me how I know sometime."

He turns around before Tony has even half a second to respond, shoving his nervous hands deep down into the pockets of his pajama pants as he stalks away. Was that supposed to be some kind of guilt trip? Or just one more dire warning in a long string of bullshit dire warnings people have been throwing Tony's way lately?

Whatever the hell it was, it's not going to work. "It's been three months!" Tony shouts, though a door down the hall slams before the first word's out of his mouth. "I've been thinking about this for three months! If I haven't changed my mind in three months, I'm not going to do it now just because you're scared of your own shadow!"

Unsurprisingly, Bruce doesn't answer.

Tony picks up his juice glass just to slam it down on the table again, wishing it would break in his hand. It doesn't. Juice slops over the side.

What an act of rebellion. He's a true badass.

But it's been three months. Three months by himself, alone every night. Three months of Loki existing only as a memory: a persistent splinter stuck in his imagination, impossible to remove even if Tony wanted to. (He doesn't.) Three months of loose ends and unfinished business. Uncertainty. Worry. Fear. Obsession. Three long, uninterrupted months of struggling to sleep every night and crawling restless out of bed every morning. Day after day of a singular thought pounding through his head.

I need to get to Asgard.

Is it even a choice any more?

"Jarvis?" he asks.

"Yes, sir?"

It's time. "Start the build. The design is finalized. Get the beamline components shaped first, let me know when they're ready for assembly, then start on the bracing structure. I want this thing ready to go ASAP."