"Prime… I'm sorry."
Bumblebee was grimy, caked in the pollution of a human city, dim optics betraying his low energy levels. The small yellow Autobot rubbed one fist across his optics, a gesture acquired from his human friend that did more to smear the accumulated road dust than clear it. Bumblebee was using his voice, the words ringing out across the unusually quiet hanger despite his soft tones. This was too serious a matter to trivialise with his usual radio clips and non-vocal chirps.
"Jolt and I were searching for hours and we barely got anywhere. We just don't know where to start!"
'Hours' was an understatement. It was almost twenty hours since Sideswipe collapsed from the shock of his brother's trauma, and Bumblebee had only now rolled back to Base on weary wheels. The sun was already well past its zenith, falling towards the western horizon. The usual business of NEST, the training drills, investigations of UFOs in the rural Mid-West, reports of strange activity in Europe, all had been put aside by a matter of far greater urgency. On the tarmac, the human soldiers of NEST worked through readiness exercises, still in a state of high alert. Here in the hangar, humans and Autobots worked side by side, poring over maps and satellite imaging. Others had replaced the scouts, refusing to surrender to the futility of attempting to search a vast, vibrant city for a single missing vehicle.
A highway camera just outside Mission City had confirmed they were looking in the right direction, but after that the trail went cold. Civil liberties, the right to privacy… the words sounded good, but they equated to no city funding for traffic light cameras, no CCTV permitted to overlook the street to any significant degree. The all-seeing cameras they were forced to avoid on visits to, say, Europe, would have been a godsend in finding Prime's lost warrior. It would help if they had so much as a vague area to start from, but Sunstreaker was notoriously close-mouthed about his downtime, and Ironhide's search of the twins' quarters, with Mudflap to aid in exploring the more confined corners, had revealed no clue as to his activities. There was no evidence they could find to narrow the search, nothing for Prime to do but wait, and comfort his Autobots with each report of failure.
Prime didn't move from where he stood beside NEST's main command and control gantry. He didn't rub at his brow or imitate the human gestures so many of his soldiers had started to adopt. Only the bright glow of his optics and the whirr of his engine vents, hitching in the Cybertronian equivalent of a sigh, gave any indication that he was a living, sentient being rather than some colossal sculpture. He was aware that his stillness was having a disconcerting effect on the humans around him. It was also providing his own soldiers with the reassuring solidity they deeply needed. A curious paradox. It was at times like this, when he was at his most weary and concerned, at his most human, that he also felt the most alien.
"You've done well, Bumblebee. You may rest and recharge before returning to your duties tomorrow. I am sure Sam will be glad to see you."
The young scout's shoulders slumped, his faintly-glowing optics falling to the swept-concrete floor.
"Not well enough. Sir, I'd like to stay…"
Prime tilted his head, optics brightening a little in surprise. "Taking Sunstreaker was not the act of a demoralised enemy. I am wary of what this suggests of Decepticon strategy. And if our newly emboldened foes decide to strike at Sam in your absence…?"
Bumblebee didn't try to hide his unhappy whine. Rationally he knew as well as Optimus did that Tracks – not long since arrived on Earth – was a competent if occasionally infuriating stand-in as Sam's guardian. That didn't stop the small yellow scout fretting through every visit to Base. Even so, he shook his head, glancing upwards and into his Prime's face.
"Sam…. I don't think..." The scout hesitated, taking the time to reset his vocaliser as he struggled to articulate his misgivings. "We found no trace of Sunny, Optimus. That just doesn't make sense."
On the gantry beside them, Sergeant Epps kicked his chair back from the monitor, the human rubbing a hand across his creased brow. The soldier frowned, unabashed by his eavesdropping.
"Bee's not wrong. Honest truth? I thought we'd hear about the battle long before anyone got to the city limits."
This time the cycling of Prime's engine vents was louder and deeper. "The same thought has been troubling me. Sunstreaker is one of our most able frontline warriors. He would not have been quickly or quietly subdued."
"Not to mention that one giant robot carting another around tends to get noticed… even in Mission City." Lennox hauled himself up onto the gantry and dropped into a chair beside Epps with a tired grunt. He ran a hand back through short brown hair, shrugging his shoulders as if he could shake off the exhaustion weighing them down. "I hate to say it, Prime, but I'm not convinced this was the Decepticons."
This time the sound rumbling deep in Prime's chest was less of a sigh than a growl. Despite his outward calm, he could feel his frustration growing. Even so, he took the time to consider Lennox's words, and the sombre looks both Epps and Bumblebee were directing toward him.
If not the Decepticons, then… He'd never hesitated to recognise the potential of these humans. Bumblebee's capture by one of their more organised subgroups, not to mention Megatron's confinement, had taught the Autobots that the small creatures were far from toothless. Even so… Megatron had been stasis locked when taken, and Bumblebee more concerned with Sam's safety and his commander's orders. Neither circumstance applied in Sunstreaker's case. Optics shadowed with concern and uncertainty, Optimus folded his arms across his chest-plates and leaned forward to study his human counterpart more closely.
"Whom do you suspect?"
He didn't show it but his spark fell as his gaze was met by two pairs of human eyes that held only matching frustration and concern… no answers.
Epps slumped back in his chair, rotating it to glance back at the screen. He shook his head. "We sure those Sector Seven assholes are out of the picture for this?"
"Frag, yeah." Lennox threw out the Cybertronian curse without hesitation, his tone vehement. The major looked Optimus in the optic, making certain the Prime saw the promise in his words. "We've got every one of them under surveillance… and, believe me, I've checked since Sides went down like that."
Prime nodded. Lennox had paid a large part in ensuring Sector Seven was fully decommissioned, and that process had been a key factor in the negotiations that established NEST in the first place. It was difficult to see any of them having a role in this, but the frown on Lennox's face suggested he was struggling to find a viable alternative.
"But…" the major pulled a hand down his face as his voice trailed off. "Damn it, I've got nothing."
Prime didn't sigh. He didn't shift or fold his arms. Deep in his processor, behind firewalls that Jazz had tested on a regular basis, Prime ran theoretical simulations and wished Prowl was here. The tactician would look at this situation and see things others would miss. Prowl would have at least some idea where to start with this mess. After all, no one had dealt with more of the twins' chaos than Prime's second.
Optimus forced the thought aside. He wasn't ready to accept that he'd lost his friend's steady guidance and subtle smile forever. Not yet… regardless of the communication that had reached him just days before. Nonetheless, his second in command was not here, and Sunstreaker's situation was more real, more urgent, than dwelling on an arrival he awaited more in hope than expectation.
Letting his vents clear in a long, soothing draft, he looked up at the main screen and the satellite images displayed there. A coastal city of almost a quarter of a million humans, living their lives at a speed Prime still struggled to comprehend. Vehicles raced along every road, locomotives hauled massive loads along their steel rails, aircraft lifted from the airport on the city limits, and even the dark waters of the Pacific were littered with vessels coming in to or out of the city's port complex. So many people, so many machines, all coming and going. And somewhere in their midst, a single stricken warrior that Prime would move Cybertron itself to find.
"Very well. Let us assume that a human agency has detained Sunstreaker. How would they move him?" He leaned forward, lowering his faceplates until he was mere feet from Lennox and Epps. "Tell me: what are we looking for?"
The humans started throwing out ideas with a new vigour. Bumblebee lingered too… until Optimus sent him to recharge, with new orders redeploying him to base for the duration his only comfort. Prime couldn't blame the young scout for being eager to help despite his exhaustion. Optimus himself had no intention of resting until his soldiers were returned to home and health.
The alternative was unthinkable.
The mech lay motionless on the medical berth. His bright red armour plates were scuffed and scratched where he'd thrashed against the metal surface and against Ratchet's gentle restraint. Even offline, sunk deep in a recharge cycle, there was a subtle wrongness to Sideswipe's posture. He looked strained, tense and ill. The medical displays and monitors stacked around him confirmed that the crude diagnosis was more than just Optimus Prime's imagination. Most were displaying a spectrum of yellow and red, Sideswipe's weak and rapidly deteriorating condition easily read by even a non-expert. Over the years, Prime had developed far more expertise in medical matters than he'd ever wanted to. Even so, he clung to a hope that the situation was better than it appeared, and that his old friend would be able to reassure him. At first sight, there seemed little chance of that.
Ratchet sat beside the stricken mech, his optics dim with exhaustion. The medic's soft voice and gentle touch would astonish most of the personnel here on NEST's home base. Not Prime. He'd seen Ratchet nurse Sideswipe and Sunstreaker back to health more often than he cared to remember. He knew the affection the gruff medic held in his spark for their wayward twin terrors. NEST's continuing failure to locate and rescue Sunstreaker troubled Ratchet on a more than professional level. It troubled them all.
Pausing in the doorway of Ratchet's domain, Optimus Prime watched his old friend study a data pad, explaining its contents to the oblivious Sideswipe in a voice too soft for Prime to make out. There was a sharp edge to Ratchet's anxiety that was deeply concerning.
Sideswipe twitched, his optics remaining dark and his processors quiet but the servos in his right hand whirring. His fist clenched, a faint grimace appearing on his face. Ratchet was on his feet within a fraction of a second, leaning over his patient and checking readings on the monitors. The medic scowled, cursing under his breath, and lay a comforting hand on Sideswipe's brow. It was a moment or two before Ratchet sank back into his chair by the berth, his eyes flicked to a bottle of clear liquid on his worktop, his stream of quiet curses intensifying.
Optimus Prime walked quietly to his friend's side, neither advertising his presence nor trying to conceal it. He paused between speaking, looking down at his stricken warrior with worried optics.
"Ratchet?"
"Prime." Whether the medic didn't recognise the implicit question or chose to ignore it, he responded with a simple acknowledgement. Optimus Prime sighed. His fingers ghosted over Sideswipe's chest-plate, feeling the fine tremors that wracked the unconscious mech.
"How is he?"
"Dying." Ratchet's answer was blunt. The medic didn't turn or otherwise respond to his leader's gasp. "And the slagging pit of a thing is that there's nothing wrong with the damn mech. Nothing I can treat. It's Sunstreaker that's dying. And he's taking his twin brother with him."
"There has to be something you can do!" The heat in Prime's outburst surprised even him.
His friend just looked at him, too bowed under the weight of his impotence to react with anger to the accusation in Optimus Prime's tone. The medic's gruff countenance betrayed more shame than anger. This was Ratchet – the medic Autobot and Decepticon had fought entire battles over, whose skills were legendary across half the galaxy. And he wasn't good enough.
"You expect me to save a patient when I don't know where he is, or what's wrong with him?" The words ground out between gritted denta. "Slag it, Prime! I'm not a miracle worker!"
Prime grimaced his apology. His large servos touched Ratchet's shoulder before his old friend jerked away. Hand falling to his side, Prime tried to repair some of the damage.
"Looking at Sunstreaker and Sideswipe, I might believe otherwise. You've kept them alive for many more vorns than anyone could have expected. They have faith in you – as do we all. And whatever has befallen them, they would know that you're doing your best, and ask for nothing more."
Ratchet scowled, lifting a wrench from the table beside him, and turning it over and over in his hands.
"My best is not slagging good enough. Not even close!" He hesitated before going on. "Don't you think I'm doing everything I can?" His words were edged with guilt, and just the slightest hint of doubt. Again he stole a glance towards that jar of clear liquid on the counter, and the syringe lying beside it.
Prime followed his gaze with a pointed look.
"What is that?"
Ratchet flinched again, looking away and almost dropping the wrench he held. He caught it clumsily before it could hit the ground, and settled, turning it over and over in his hands. The old Autobot medic shook his helm, his scowl fierce.
"For Primus' sake, Optimus! There's no physical reason for Sideswipe to be as weak as he is. His symptoms are ghosts… echoes… the result of his processor trying to interpret sensor data and error routines coming through his private comms from Sunstreaker. Whatever happened to poor Sunny, it wiped out the usual filters both of them have to protect against that sort of thing." Prime noticed his medic's use of Sunstreaker's affectionate nickname, but didn't call him on it. He frowned.
"If you can block that data…"
He fell silent in the face of Ratchet's glare. The grizzled mech was building to a conclusion he didn't like. The least Prime could do was hear him out.
"I could set up an electromagnetic interference field. It just might damp off their subconscious com systems, and the corrupted algorithms sending Sides' systems haywire. I reckon we'd have a fifty-fifty chance of the sudden shock killing Sideswipe. Which is kind of irrelevant when it'd almost certainly kill Sunstreaker outright, and Sideswipe wouldn't survive the loss of half his spark.
"So if I can't treat Sunstreaker, and I can't stop his signals reaching Sides, the only thing I can do is try to ease Sideswipe's symptoms, right?" Ratchet paused, scowling. Prime just waited as his friend's voice softened to a murmur. "So I started looking at the symptoms themselves, and you know what I found? Sideswipe is displaying a classic poisoning response, and given the obsession with the stuff on this wretched planet, I'd stake my wrench on it being hydrocarbon poisoning."
Nor Prime did speak, frowning. "Hydrocarbon…?"
Ratchet waved a vague hand. "Vehicle fumes. Fuel. Paint. Solvent. Something of that nature. Whatever it is, Sideswipe's frame is reacting to it. Prime, Cybertron was never rich in organics – we're not designed to process them. We can't flush the impurities and aromatics that just won't burn clean. That's why I have to update the organic subsystem patches in every damn round of physicals. The number of mechs I've had to treat because they can't tell the difference between decayed vegetation and decent mineral oil…!"
"But Sideswipe and Sunstreaker both have that subroutine installed," Prime objected, interrupting his friend's rant with a certain amount of caution. Ratchet shook his head tiredly.
"Slag it, Prime! Far as I can tell, Sunstreaker's processors are scrambled to the Pit and back. A patched, second level routine like that hasn't a chance of functioning, even if Sunny's analysers managed to identify the problem." The medic rubbed his hand across the chevron on his brow. "I'm reading a low level and virtually useless system-flush protocol in Sideswipe. That has to be an echo of Sunny. Sideswipe's own self-diagnostics are checking his toxin levels and environment readings every few breams and cancelling the flush. And that's pointless because whatever signals he's getting from Sunstreaker just re-establishes it moments later. Sideswipe's organic filtration algorithms aren't helping his twin any because they don't have any information on what the problem is, so can't send specific instructions. And all this is taking more energy than either of them has to spare."
Again, Prime simply waited, letting Ratchet spell out the problem in his own way.
"There is one thing… only one… that I can think of that might help Sunstreaker."
The quiet announcement didn't exactly fill Optimus Prime with confidence. He cycled air through his vents. "Anything."
Ratchet's eyes rose again to the liquid and syringe on the side bench. For a long moment he remained silent. When he looked up at Prime, his expression was anguished. Optimus Prime had to strain to hear his friend's voice. It barely rose above a whisper, as if the medic was horrified at his own words.
"If I inject hydrocarbon contamination directly into Sideswipe's energon lines… If I can get a strong enough response from his processor… there's a chance that Sunstreaker's maintenance and filtration system will take a command from Sides instead of the reverse. If I can get Sunstreaker to build the right binding agents… it might just keep him alive long enough for us to get him out of whatever mess he's in."
Prime's optics irised a little wider, his expression thoughtful. "You said hydrocarbon poisoning was dangerous. Injecting it directly…?"
"Human medics, they have an oath. A code they swear to uphold. It starts with 'First do no harm...'" Ratchet shook his head, the movement sharp and angry. "It'll hurt," he admitted bluntly. "A lot. Probably worse than anything Sideswipe's ever been through. Even if he manages to stay offline, he's going to be writhing in agony."
"You could give him something to deaden the pain?"
"No. I can't. I need that reaction to be as strong as I can make it, short of killing him myself. Because – curse it to the slagging Pit, Optimus! – here's the thing: even then it might not work. I'm trying to cure a patient by poisoning his brother – no one's ever done it before. No one's even thought of trying it!" He paused, venting hard. "It might save them. And it might just make their last hours an eternity of torment."
"And if you don't?" Optimus Prime's optics were as dim as his old friend's. His spark felt cold, torn.
Ratchet sighed, reaching out unconsciously to stroke the side of Sideswipe's helm.
"We might as well start engraving a second casket to lie beside Jazz's. They won't last another day. I'd be surprised if they last the night."
Prime and Ratchet shared a long look, the shadow of old grief and the prospect of new mingling in their sparks. Both hated the decision in front of them, both knew they had no choice.
"Do it," Prime ordered softly.