DOA.

How could it be that end of the world could be summarised in three little letters? A few little strokes of a pen; they would be so quick to write. And they were spinning around in his head now; it was as if those little letters were the only ones he knew.

DOA. You couldn't make much from them. Doa, oad, oda, ado. Much ado about nothing. He wished.

The plastic chair was hard and unforgiving beneath him. Don shifted, but he'd already learned that it was impossible to get comfortable on these seats. Somehow he doubted he'd ever be comfortable again.

The world was moving past his eyes. People came and went around him, sitting and standing, running or walking, but they all seemed to be moving in a different span of time from him. They were moving on into the future; he was stuck fast in the present, clinging to the past as though it could raise him from the depths of the ocean.

"You coming over for dinner tonight? Dad's volunteered me to help with the cooking." Charlie was grinning as he leant over the plastic wall over Don's desk, depositing a folder down by his brother's keyboard. "The algorithm you asked for."

"Thanks, Charlie!" Don exclaimed as he rifled through the folder. "This is exactly what we were hoping for. Hey, David!" The other agent wandered over from the other side of the office, followed by Colby, and both nodded greetings to Charlie as they approached.

"What've you got, Don?"

"Tomorrow morning downtown, get a team together. I'll be through for the brief in a moment."

The agents nodded and departed, and Don spun his chair round again to look back at his younger brother. "Dad's letting you cook?" he repeated, smirking a little as Charlie's face fell in response to the amusement in Don's voice. "Or does that mean he wants you to order in pizza?"

"Stranger things have happened," Charlie replied haughtily. "And no, actually." He began to turn away. "He wanted Chinese."

Don's laughter chased Charlie out of the office.

Yesterday. That had only been yesterday. One day ago, twenty seven hours. Charlie would have known how many minutes, how many seconds, but that was beyond Don. All he knew was that the last four of them had been plagued by those three letters, and that they had been the worst of his life. And it was never going to get better.

And he hadn't even called his dad yet. Heaven help him, he hadn't even told his dad.

"You want a beer, Don?"

"Don't I always?"

Alan Eppes chuckled as he headed for the kitchen, gesturing for his eldest son to settle down at the table. "Food should be ready soon. How's it going in there, Charlie?"

Charlie appeared from the kitchen as his father vanished into it, scowling as both his brother and father grinned. "It's really not that funny," he protested, positioning three plates and the accompanying cutlery around the table. "You two have known I can't cook since I was five. There's no need to keep going on about it."

"You mean since you managed to burn waffles?" Don grinned, and gestured to the table. "You forgot the coasters."

Making a sound oddly like a growl, Charlie descended once more upon the kitchen – at which point the doorbell rang. "I'll get it," Don said easily, taking his time about standing up and heading into the hallway purely because he knew how much it would aggravate his brother. The delivery girl was cute and Don found his mind wandering, but the bill brought him sharply back down to earth.

"Fifty bucks?" he objected as he returned to the table, paper bags in hand. "What the hell did you order, Chuck?"

"If you call me Chuck one more time, I swear-"

"There'll be no swearing in this house," Alan said firmly, steering Charlie into a chair and passing round open beer bottles. "Not unless you both want to be grounded for the next month."

Silence for a moment, then Alan's façade of severity crumbled into a broad grin, mirrored on the faces of his children.

"Hi, Megan. No, I'm fine. You don't need to come over. Could you phone my dad? He needs to know – DOA – I can't... Yeah. Thanks. Bye."

He closed the phone. Had Megan heard, as he had, the strangeness of his voice? The monotony, the flatness; it was not his voice. He had become someone else; a stranger, someone he would not recognise if he looked in the mirror. And he didn't want to know himself. Because it was his fault. All his fault.

"OK, listen up. We've been informed by a reliable source that the gang will probably strike at approximately two pm this afternoon. That gives us five hours to set up a full perimeter around the train station. We've got LAPD on our team for this one and I want agents on every platform. There's no reason to expect that they'll change the plan they've been working from for every one of the other attacks, so we can expect them to arrive by train from any direction; possibly more than one, if they split up. We've got men inside the station control areas already so if anyone's recognised, we'll be tipped off before the trains even get into the stations. It's too much of a risk to stop the trains because chances are they'll just open fire on board; we'll need to wait until they get off.

"If they're not recognised, letting them get into the main area of the station is our last resort, understood? That's always where there are more potential victims and therefore where they tend to open fire. So we stop them getting there at all costs. Now get into your teams; you'll all be briefed on your exact tasks. We're counting on you."

The FBI agents dispersed at a nod from Don, dozens of them streaming out of the open plan briefing room he'd been assigned to organise the agents. Megan, Colby and David approached, but before the team could talk Charlie barrelled through the door.

"Charlie? I thought you weren't coming in today?" It was Colby who had spoken, looking from brother to brother with a grin. "Don said you were feeling a little off."

"He exaggerates," Charlie said cheerfully. "And with the combination of everything he ate and drank last night, we should all be surprised he's not still curled up under the sheets."

"Aspirin works wonders, even for the legendary Don Eppes," Megan observed with a smile, and Don raised his hands.

"Cut it out, guys, I thought you were on my side?" He shook his head ruefully. "What do you need, Charlie?"

"It's just about today. It's nothing concrete; I mean, the math suggests that everything should be fine, but..."

"What is it, Charlie?" David prompted, cutting through his rambling and succinctly doing the job for the rest of the team.

"There's something wrong about all this. It's just a feeling I have. There aren't any anomalies in the data to reinforce it, but I think something will be different about today's attack." There was something different about Charlie, too. Maybe it was a slight hangover or maybe just the nagging worry he was describing, but he looked off.

Don wasn't so easily convinced. "So you're not basing this on anything? Just... a feeling?"

"Yeah," Charlie shrugged, seeming to realise how feeble it sounded. "I just don't think you should go in there today. I need more data, something more to investigate."

"More data? Charlie, if we don't bust these guys today then you'll get more data at the cost of who knows how many lives! Their leader is ex-military, remember? And he thinks America's the reason his wife is dead. He's out for blood, Charlie! We've been following them for weeks, and we might not get another chance. We've got to go for this."

"I know," he said reluctantly, hands running through his hair. "I know you have. Keep your cell on, I'll ring you if I dig anything else up."

Don wished so many things. He wished he had listened to Charlie, trusted his brother's instincts. He wished he had phoned him before heading into the train station, he wished he hadn't turned his cell off after all. He wished he hadn't listened to his voicemails two hours too late, and heard his brother trying to warn him again.

"Agent Eppes?"

His thoughts were disturbed by this voice, yet he didn't look up. It was as though the man was talking to someone else, someone in a different world. Someone who still felt alive.

"Agent Eppes. Don."

He looked up at that, at least.

"I'm sorry, Agent, but we'll have to move Mr Eppes out of the ICU soon. Do you want to see him?" The doctor was young; she had to have only recently become a resident yet already there was a stoical detachment about her face and voice. She had seen this before, she knew she would see it again, and it just washed over her. The same way that after a while his job washed over him. You had to let it, because otherwise it destroyed you.

Not that he needed a job to do that. Family sufficed just as easily.

"Professor," he said mechanically.

"Excuse me?"

"He's a professor. Math. At CalSci."

The doctor nodded, gentle and almost too understanding. "Are you waiting for anyone, Agent Eppes? Family, friends, anyone you want to do this with?"

"Do what?" Don said brazenly. "He's just my brother. I don't need anyone holding my hand to go and see him."

"You don't have to do this on your own. There's a phone, if you need to tell someone-"

"Tell them what?" Don demanded, and his temper flared. "There's nothing to tell! It was an accident, just an accident, he'll be fine, he wasn't that badly hurt! It was just a bullet, just one bullet."

For a moment the doctor's calmness changed to confusion, which faded quickly into sympathy. Don didn't like that look.

"I'm sorry, Agent. The paramedics tried, but there was nothing they could do. He was dead on arrival."

There it was again. DOA, DOA, all the time, the letters bouncing around in his head until they lost all meaning; they were just letters, a code, a code that would tell him what to do, a code that Charlie could break, but Charlie was not there...

"Stop saying that! He's just acting, pretending in case the bastards who did this come back – but it's not for real, you've got to understand that, you've got to help him! You can't just give up!"

"I'm so sorry, Don. Do you want to see him?"

And then the confidence collapsed. Don shook, and when he looked up at the doctor he saw her through a veil that blurred her into a indistinct colours and shapes.

"He can't die," he whispered. "He's my brother. And I never got to say – I never told him that I loved him." He was crying in earnest now, though he had not noticed; silent tears spilled down pale cheeks. "But he'll come back," he said suddenly, and though he was still crying his eyes lit up. "He wants to know I love him. That's what he's waiting for. If I tell him, he'll come back!" A new sense of purpose filled Don. He felt stronger, he felt complete again; he stood up and felt fire in his heart.

But the doctor only laid a hand on his arm, her eyes telling Don things that he refused to accept. "You can tell him, Agent, but he won't hear you. Not any more."

"Damn it!" Megan looked over at Charlie in surprise as he cursed, slamming his cell phone down onto the table.

"What is it?" she asked, walking over to get a better look at the papers strewn out over the tables, and the incomprehensible markings on the whiteboard of his makeshift office in the FBI building.

"I've got to get through to Don!" he practically shouted, rifling through the papers.

"What's happened?" She didn't need her profiling to interpret his mood.

"I said earlier I had a bad feeling about all this. Well, one of your tech people ran the suspects through your systems again using some different variables I'd come up with. And guess what? Four out of six of them all have links to a black market group."

"We already knew that," Megan pointed out. "That's where they got the guns."

"Yes, but when I left our suspects out of the picture and focused in on this group, there were members within that with possible links to a case of missing explosives. What if our suspects weren't just buying guns? What if the shootings were just the decoy, letting us get comfortable while they prepared the real weapon?"

"A bomb," Megan breathed, and Charlie nodded. The next second, she was running for the door, Charlie hot on her heels.

He was proud of his brother. He always had been. But sometimes he wished Charlie could have been born without a scrap of intelligence. Because then he wouldn't be walking along this cold corridor with legs made of lead, he wouldn't be fighting the world just to move or even force air into his lungs. If his brother had been stupid it would have been him lying on the gurney, it would have been him that could be labelled with the three cold letters DOA. And how he wished it had been.

Don checked his watch. One forty five. He opened the comms channels. "A and B, teams in position?"

"Affirmative."

"Sir."

"Platforms secure?"

"Confirmed."

He nodded, and looked at his companions in the back of the van – Colby and David, with two other agents.

"Any word from Megan?" he asked David.

"None yet. I guess LAPD haven't been as successful in monitoring the trains as they'd hoped."

"Time to do things the old fashioned way, huh?" Colby said with a grin, albeit a tight one. None of them were looking forward to this.

The minutes dragged by. Then-

"Gunshots!" Colby exclaimed, and his hand was on his own gun before the screaming even started.

They were early. Don's hand flashed back to the comms. "Report!"

"LAPD were recognised on the platforms!" the first agent to respond shouted over the airwaves from inside the building, clearly running. "Two suspects have opened fire, the other three are heading for the stairs."

"Let's move out!" Don yelled, flinging open the doors of the van and jumping out. Two more vans followed suit, emptying their cargo of blue and yellow vested agents who began sprinting for the doors to the station, while civilians streamed out. A full scale evacuation beforehand would have been better but the shooters would have been scared off, and there would have been no chance to stop them...

But suddenly came the sound of rapid footsteps, coming from the other way to all the rest. Without warning Megan was standing beside him, shouting words that Don hardly heard, because Charlie came running up after her. His appearance barely registered in Don's mind because it was just so impossible that he could be there at all – that he could be there, unprotected, that he could be running straight towards a live crime scene...

"Don, listen!" Megan shouted, "There's a bomb! We've got to evacuate the area; they've got a b-"

She never even got to finish the warning. At that moment, the world pulsed outwards from the station, a great ball of fire that turned the air to poison and rented the air with sound. The walls were flung outwards, the ceiling upwards, as the entire structure of the station exploded. The civilians still streaming down the steps were flung forwards in the wake of the blast, and even in the middle of the street the agents were knocked down by its force.

That might have been the end of it. They could all have walked out of there in one piece. Don recalled the mind numbing fear that was like a raw taste on his tongue, recalled choking on dust as he stood up and shouted his brother's name. And he recalled that he had felt elation (though now he could not imagine how it felt) upon hearing his brother call back, seeing him stand up; seeing him alive.

One suspect made it out of the building, and he came out shooting.

It was a rogue bullet. It could have hit any one of them; it could have hit none of them at all.

But it hit Charlie.

There wasn't much blood. Not as much as Don would have expected. Charlie just crumpled silently, his last smile fading from his lips. Don didn't believe it. He couldn't, wouldn't. He just moved on automatic, running to his brother's side and dropping to his knees; he skidded the last few inches but didn't notice the ground ripping his pants.

The paramedics they'd already had on standby were racing forwards even as Don leant over his brother, desperately pressing his hands down on the hole in his chest, running bloodied fingers through his brother's soft curls, staining black with red, tried to scream as though that would force his brother back into life again...

How long had he sat there before they'd dragged him away? He didn't know. Charlie would have known that, too. But he didn't. He'd never know a fraction of the stuff Charlie had known, but Charlie was everywhere. He had always said, after all, that life was math and math was life. So everything reminded Don of Charlie. Corridors had right angles, the lighting was a variable, decision theory governed whether he would take the lift or the stairs...

David and Colby had been holding him up, he knew, and the world had begun to pass dimly on in front of him much as it had been ever since. But some of the words of the paramedics had permeated his detachment.

"No pulse."

"Hypervolemic shock."

"CPR..."

"Exsanguination?"

And that final, fatal pronouncement.

"DOA."

He didn't know what had happened to the shooter. He thought the man was probably dead by now, because he had probably fired more bullets. Maybe Don himself had killed him, though he didn't remember even holding his gun. But he wouldn't be surprised. He didn't know why Megan had let Charlie come to the scene, he didn't know why his brother had wanted to come. It didn't matter now.

Terminal ballistics. That was what it was. The study of how projectiles behaved on contact with a target. It was so much easier to think about that way, and Don began at last (too late) to understand his brother. Facts were cold, hard, detached; it was easier to think projectile than bullet, easier to say target than Charlie... Statistically it was more likely for a randomly fired bullet to hit nothing than a person, in an uncrowded area. And it was more likely not to hit a vital organ than to hit one, since there were a finite number of them in the human body. The numbers at least had been on Charlie's side. But Charlie and his chaos theory would have said that nothing was random, and it had not been a lucky day.

And then without realising it he was standing by the large window to a room with a single bed, and he was staring at his brother. His little brother, his face pale and still and cold. And Don could not go in. He couldn't enter the room, he couldn't stand beside his brother because it was his fault, all his fault, and he had never even had time to say goodbye.

His brother had been dead before he hit the ground, and now it was Don that crumpled to the floor, leaning with his back to the window, and sobbing his heart out onto the cold plastic linoleum.

That was how his father found him an hour later, still sobbing though he barely had any tears left. And without a word spoken Alan sank to the ground beside him, and drew him into a crushing hug. Now the letters haunted them both, and they always would.

"Hey, Don?" Charlie, leaning against the sofa, deposited his half empty glass on the coffee table next to his brother's feet. They had migrated to the living room and Alan, on a nearby armchair, was so content that he did not even chide Don for dirtying the furniture.

"Yeah, Chuck?" Don smiled easily at his brother, ruffling the younger man's curls from his position of power above where Charlie sat on the floor.

"Love you."

"I know, Chuck. I know."

He had thought there would always be time. But there wasn't. There never would be again.

"I love you too, Charlie," he whispered, drowning out the echoing letters in his mind. "I love you too."