Author's Note: I am assuming in writing this that Thirty-Six Hours took place in its originally intended point in the timeline: just before Charlie got his clearance back, between 5.03 and 5.04.

Charlie wasn't scared, and he wasn't shocky, not really. He'd gotten over wanting to throw up hours and hours ago, but he still couldn't stop shaking. He'd felt so useless, so angry at his own powerlessness when first the boy Doug, and then David, had refused to listen to him and brought the pile down on top of themselves. And now two people were dead who could have been alive, and it had almost been five. The only way he could have felt worse was if it had been Don trapped in the wreck instead. Maybe Don would have had enough sense to listen to Charlie. Then again, he might not.

Charlie glanced sideways at Don, in the driver's seat of the Suburban. But Don's profile was remote and unreadable, to Charlie at any rate. The sun was coming up over the mountains ahead, the light reflecting off Don's sunglasses. It was morning, unbelievably. Charlie felt like he'd just lived through at least five consecutive nights. He leaned his head against the window, idly tracking the models and colours of the cars passing in the opposite direction. Commuter traffic was beginning to fill the other side of the freeway, although they had the northbound side pretty much to themselves.

A good thing too, Charlie realised, as Don gave a little gasp and a jerk that made the SUV veer half a foot towards the median. He steadied the wheel, opening his eyes very wide behind his shades. Charlie bit his lip. He was so used to trusting Don's driving that he hadn't even considered how tired Don must be, but that had clearly been a microsleep.

"D'you want me to drive?" Charlie asked.

"Hey, you're in even worse shape than I am. At least I got a nap, unlike you."

"I don't think it counts as a nap if you fall asleep with your head on a table and no-one has the heart to wake you even when your spine's bent in two."

"Next exit and we're nearly home anyway," Don said, putting his window down an inch and flipping on the radio.

"—from the wreckage. The death toll continues—"

Don made an annoyed noise and switched to CD. Inappropriately cheerful Britpop bubbled from the speakers. Charlie was pretty sure that was a mix he'd had when he lived in England, and wondered when it had ended up with Don. The music brought up memories of his post-doc work and Susan Berry and the flat in north Cambridge. It felt so long ago. And it was clichéd to say that the Charlie Eppes of those days had been a different person, but the truth was more like he'd been three or four people since, all of them very young.

Whatever associations Don had with the song, he evidently didn't want them either, because he turned it off after thirty seconds and said, "Okay, talk to me, Charlie. Keep me awake."

Because it was in his head, Charlie said, "If it had been you, would you have gone into the pile like that?"

The corner of Don's mouth twitched. "Probably. Probably not. Because it was you telling me not to, and I know you know your stuff."

That was another damn good reason for Charlie to work with Don. Don seemed to guess something of what Charlie was thinking, because he said, "Don't worry about it," with a yawn.

"It would be kind of ironic," Charlie said, "if we died from sleep deprivation, considering that was what caused the crash in the first place."

Don snorted. "Well, that and good old corporate America. There's always something about the industrial disasters. Twenty-five bodies and a toxic cloud over an urban neighbourhood? Whoops, unfortunate side effect of business, not what we intended. Whaddya mean, our responsibility?"

"Like the toxic waste buried at the elementary schools, remember that?" Charlie said. "But the responsibility should attach to any reasonably foreseeable consequences of the act."

"Damn straight." Don shook his head a little. "But does it? Hell, no. Corey had the cheek to start talking to me about my crossing lines, and I couldn't stand listening to him, so I was like Watch your head, and then..."

Charlie winced. "So, uh, how big is the new dent in the Suburban?"

"I shouldn't have done it, not front of Nikki. Shouldn't have told you about it, either." Don glanced over at Charlie, eyes invisible behind the opaque lenses. "C'mon, Charlie, is there nothing I'd do that would make you stop looking at me like that?"

"Like what?" Charlie asked. He hadn't been staring Don down in his wooziness, or anything, had he?

"So trusting," Don said, a hoarse edge to his voice. "My brother, right or wrong."

"Plenty of things, theoretically," Charlie said cautiously. Post-therapy Don still took some getting used to. "You haven't done them yet. I don't believe you will."

"See, that's exactly my point," Don said, eyes firmly on the road again.

Charlie hesitated. If they were going for brutal honesty...the whole conversation had a surreal, dream-like feel anyway, so he wasn't certain he wasn't asleep already. "There were a couple of moments...Phil's case, especially...where you had me worried."

"I don't know whether that relieves me, or not," Don said quietly, as he swung the SUV onto the offramp. "It's like...I cross lines, and then the lines move."

This was one of the ways Charlie didn't understand Don; to him, the lines were the lines. He knew where they were. He didn't feel the need to go check them the way Don seemed he ought to be used to this, that his shining certainties simply weren't there for other people, even if it usually happened with math. He shouldn't feel this desolate. He wished Dad were here. Even if he couldn't make everything all right, like he could back when Don and Charlie were still kids, he would at least be better at comforting Don than Charlie was.

The Suburban roared down the quiet Pasadena streets. Sunday morning; people mowing their lawns, going to church, tut-tutting over the bad news on the radio. It looked so odd.

"You know," Charlie said at last, as Don pulled onto their own street, "if you were really that sort of person all the way through, it wouldn't bother you like it does."

"You sure you're Charlie and not Dad?" Don asked.

"I'll take that as a compliment," Charlie said dryly. As the SUV pulled up to the house, he wondered if Don were planning to go on to his apartment. Well, Charlie decided, he just wouldn't leave the car until Don was already out of it. But Don shut off the engine, threw his sunglasses onto the dash, and jumped out readily enough. He'd barely locked the Suburban behind them, though, when he went "Whoa," and leaned on the side of the SUV.

"You all right, Don?" Charlie said, running around the hood to his brother. Don hadn't been close enough to the wreck to be dangerously exposed, right? "Don?"

"I'm fine, I'm fine," Don said, sliding down the side of the car. "Just really tired."

Charlie's own breath wasn't quite right as he crouched beside Don. It was scary to see him crumple like that. Still, at least it sounded like there was nothing worse wrong with him than adrenaline crash. Charlie put a hand on Don's arm. "You should've let me drive."

"Yeah, yeah," Don said, which Charlie found reassuring. He stretched his legs out in front of him. "You did good today, Charlie, you and your bots. You should tell CalSci to sue Corey and Desert Pacific for the cost of them."

"Call it a trial under field conditions," Charlie said. "A moderately successful one."

"Listen," Don said, "don't go beating yourself up over the people we lost. It wasn't anything you did or didn't do."

"It's just, it's just that we should have had four lives instead of two. Done twice the good."

Don opened his eyes. "Buddy, look, for Jeffrey Knight, for William and his mother, you did an infinity of good. Can't better that."

Charlie felt a bit better, thinking about that, so he smiled at Don, and didn't even start arguing about transfinite numbers. So for Don to have brought that up, either he could read Charlie's mind, or—

"You going to follow your own advice, bro?" Charlie asked.

Don threw him his gotcha grin, said "Charlie," pulled Charlie in and gave him a noogie. Charlie made the requisite little-brother protest—not that he minded, really—and pulled away, drawing his knees up under his chin.

"I said to Dad, the other day," Don said muzzily, "that it was all compromise and politics and toeing the party line. I forgot that sometimes it isn't. Sometimes it's not complicated at all."

Charlie looked over at Don, who was smiling faintly, his eyes closed again. Charlie bit his lip. Don hadn't been given the chance to work out his problems with the FBI, without Charlie and the issue of his clearance breaking in and spoiling the data. Would he even have half the problems at all, without Charlie? Charlie had been in academia long enough to know what "politics" meant. He had never done anything but make Don's life harder, right from when they were kids.

Charlie shut his eyes for a second, and jerked them open when he remembered what he'd seen—what he'd dreamed—last time he'd shut them. It didn't mean anything, it wasn't some secret psychological thing; he'd been thinking all along in the back of his head about impacts and collisions, simple Newtonian mechanics, and Don's voice had woken him. Dreams could be triggered by whatever woke you, like the Dali painting, you only thought they'd been going on for hours. It didn't mean anything, the dream-Don looking him in the eye and saying "Charlie," even though it was already too late. Charlie gave a shudder, residual panic, and Don reached over and patted his arm, without giving any other indication of consciousness. Judging by the way Charlie was starting to feel Don's weight against his shoulder, Don was half asleep already.

"Hey," Charlie murmured, "you do realise there's a bed in there with your name on it?"


"Dad's probably put clean sheets on it and everything."

Don mumbled something semi-coherent that Charlie understood to mean that in that case Don would have to shower and he'd probably accidentally drown himself in the process. Charlie shook his head and leaned back. Maybe Don had the right idea, he could just rest here for a bit. The sun was warm on his face, the last of the shakes were wearing off, and with his back to the Suburban and Don at his shoulder, he wasn't going to fall over...

Maybe there was no point where he could say he should have stopped interfering in Don's life. They'd always been connected, like quantum-entangled particles. The equations played across the inside of his eyelids, the solution tantalisingly just beyond his reach...

The next thing he was much aware of was orange-blossom-and-vanilla scent, a kiss pressed into his hair, and Amita's voice saying, "I know I'm exhausted, but not so much as to sleep sitting up in the driveway."

"'M not asleep," Charlie said, scrambling, wobbly-kneed, to his feet to prove his point. "Thinking." He wrapped an arm around Amita and drew her against him, burying his nose in her silky hair.

"Are you going to tell me the same goes for Don?"

Charlie looked down. Don was still on the ground, tipping sideways a little without Charlie as a counterweight, and—not exactly snoring, but his breathing was clearly audible. Charlie leaned down and shook his shoulder. "C'mon, get up. Wakey wakey, Donnie."

"Uhh," Don said without moving. Charlie looked at Amita, who raised her eyebrows.

"I figure we could carry him," she said cheerfully. "Between the two of us."

Don's eyes shot open. "Okay, okay, I'm standing up, look—" He hauled himself upright, using Charlie's outstretched hand and the side of the Suburban for leverage.

"Well, that was effective," Amita said, and began to laugh, with more than a hint of hysteria. Don started laughing too, not his usual short "hah!", but the helpless breathless sort of laughter that had always started Charlie off too, ever since they were kids.

"C'mon inside," Charlie said, choking on the giggles. Don's arm slung across his shoulders at the same moment as Amita's wound round his waist. "We're home."