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[Earth, Autobot outpost Omega-1, Yellowstone]
When Optimus returned from patrol along a long-familiar route, he looked oddly stirred. As stirred as the ever-composed Prime could possibly appear.
Arching an optic ridge, Ratchet watched in silence as Optimus drove onto the base through the bright vortex of the groundbridge — three miles per hour faster than usual. Then he remained in alt-form for a few seconds, exhaust stacks puffing thoughtfully. Only after that did Prime transform, slowly, with a few strange hesitations.
“Everything quiet?” Ratchet asked evenly, lifting a lever and shutting down the teleport.
Optimus raised his gaze with visible delay, as if he hadn’t fully returned to reality yet. His optics lingered on Ratchet for a moment, his EM-field rolling out in a warm wave, and only then did he give a faint nod.
“Quiet,” Optimus replied. His voice sounded as steady as ever, yet there was an unfamiliar depth to it, something hidden beneath his usual restraint.
Ratchet frowned with concern. He knew Optimus far too well to take that at face value. But the Prime didn’t elaborate.
“I’ll file the report while the others are still out.”
“Alright,” Ratchet said, a little more at ease, curiously nudging the bond between their Sparks.
Answering with a warm pulse of affection, Optimus gave a gentle nod and headed deeper into the base. Ratchet watched him go, observing and listening closely. The steady rhythm of his steps, flawless mechanics and hydraulics, the smooth shifts of armor plating. The Prime’s EM-field was slightly wound tight, pulsing at an unusual frequency, but there was no alarm in it either. Only a strange shimmer — a rare hint of impatience.
Ventilating briefly, Ratchet waved off his uneasy thoughts and returned to the main console. If something were truly wrong, Optimus would have said so.
The oddities didn’t end there. The patrol report uploaded to the server was unusually brief for a Prime. An hour later, the duty roster updated, and the medic found one of his own shifts missing — the night one he had planned to spend on scheduled maintenance of the backup generator. That was when it became obvious: Optimus was definitely up to something.
Close to midnight, Ratchet was still in the medbay, the generator set up on one of the repair platforms. So when his sparkmate’s heavy footsteps finally sounded in the corridor he wasn’t surprised in the slightest.
“Ratchet, are you…?”
“Busy.”
As always, the sharp reply didn’t faze Optimus at all. Softening his steps, he came closer, carefully resting a hand on one of the medic’s shoulders and peering past the other. His EM-field reached out in a smooth touch of comfort and affection.
“While I value, endlessly, all the effort you put into keeping our base running smoothly,” he began, choosing his words with care, “the generator can easily wait until tomorrow. Right now, I require your professional opinion on a most fascinating Earth phenomenon.”
Ratchet froze. He winced out of habit but didn’t turn around right away — only straightened up, tidied the wiring beneath the generator’s main panel, and set his tools aside. Only then did he turn his helm toward Optimus, his gaze meeting the Prime’s stern profile.
“An Earth phenomenon?” he echoed, the words edged with mild irritation, though no real anger remained. “You come back from a routine route, ignore my report requests for hours, edit the duty roster, and now — a phenomenon. You definitely found something out there.”
Optimus held his gaze. Without looking away, he gently tightened his grip on Ratchet’s shoulder — not insisting, but as if asking for trust. His EM-field stayed even now, the earlier tension gone, yet filled with a heated alloy of restrained nervousness, quiet confidence, and anticipation.
“Yes,” Optimus confirmed calmly. “Though I first detected it on a previous patrol. Only today did I determine how it might be used to our advantage. I didn’t want to discuss it until I was certain it wasn’t a sensor error. And now… I truly need you.”
His broad hand slid smoothly over Ratchet’s shoulder, brushing a seam between armor plates and moving slowly along his side before settling above the hip fairing. Ratchet studied the Prime’s faceplate in silence. Half a second. One and a half. It was impossible to stay genuinely annoyed when his sparkmate’s powerful field wrapped around them both, shimmering with fondness and understanding, while the thin thread between their Sparks slowly warmed with shared affection. So the medic lowered his gaze, vented, and finally muttered:
“Alright. Talk.”
“Better to show you.”
And the deep voice so close to his audiosensor extinguished the last flickers of irritation in his emotional circuits.
“…Why can I never tell you no?”
Bumblebee was on duty in the command center — the medic’s night shift had gone to him. Spotting him at the consoles, Ratchet shot his sparkmate an irritated, suspicious look. The scout was almost certainly in on this.
“We’ll keep our comms online,” Optimus instructed quietly, entering coordinates for the bridge. “If anything unusual shows up on radar, alert us.”
“::Got it, will do!::” Bumblebee chirped, doors twitching as he pulled the lever.
The groundbridge whined to life, opening into a glowing vortex. Casting the medic a soft look, Optimus stepped toward it first.
“::Have a nice evening!::”
Ratchet only rolled his optics when he noticed Bumblebee squinting after them with open amusement.
And then the groundbridge cast them out into the night, and the medic hastily recalibrated his optical sensors to adjust to the new light levels. Optimus’s EM-field — commanding yet gentle — blended soothingly with his own.
“Alright, where are we?” Ratchet scanned their surroundings, but only endless tree trunks rose around them — they were deep in a forest.
“Wyoming,” his sparkmate said, carefully resting a hand on his shoulder. “Yellowstone National Park lies about thirty miles to the south.”
“And what are we doing here?”
Optimus’s fingers slid thoughtfully over the medic’s backpack.
“There’s something you should see. But we’ll reach the destination on wheels.”
Ratchet lifted his optic ridges, silently demanding an explanation. His sparkmate’s optics answered only with a playful flash; Prime cheekily flicked the medic’s antennae, transformed, and took off through the forest — toward the gray ribbon of an empty highway visible between the treetops. Snorting in irritation, Ratchet raced after him.
“Think you can outrun me, truck?” he huffed over the commlink, easily catching up once they hit the road.
“I don’t stand a chance,” Optimus agreed good-naturedly, maintaining his speed. “However, you are driving in the oncoming lane and may attract police attention.”
“You worry far too much about humans…”
“In this case — exclusively about you, oltfrent.”
Flustered, Ratchet swerved slightly in his lane, thought for a moment, then switched on his emergency lights. An ambulance overtaking a heavy truck in the oncoming lane wouldn’t raise suspicion. Quite another matter that this ambulance stayed perfectly aligned with the truck’s rear axle, occasionally brushing its side against the frame.
The steady rhythm of motion truly was calming. Tires warmed gradually, suspension softened. Optimus’s engine rumbled low and even, his EM-field humming with warmth. Ratchet caught himself thinking it wouldn’t be so bad to climb onto Prime’s chassis right now, wrap himself around the cab, and slip into a light hibernation for an hour or two, lulled by the sound of his perfectly tuned systems at work.
“Almost there,” Optimus assured him half an hour later, turning off the highway.
Of course Prime caught the way the structure of their bond softened, and he sank a little more comfortably onto his suspension. Ratchet responded with an indistinct but clearly agreeable hum and followed.
For another half hour, the two Cybertronians drove unhurriedly along a gravel road until a parking lot appeared ahead, unsurprisingly empty at such a late hour. Optimus passed it without hesitation and kept going in alt-form until the gravel track faded into a barely visible strip beneath their wheels.
“From here, it’s only a five-minute walk,” he said evenly, returning to root mode.
“Had I not known you for so many years,” Ratchet snorted, transforming as well, “I’d think you were trying to kidnap me.”
Optimus gestured for them to continue. Only then, walking at an unhurried pace along the trail, did he ask,
“Would you want me to?”
Startled, the medic shot him a look and caught the familiar soft smile tugging at the corner of his sparkmate’s mouth. The bond between their Sparks slowly thickened, pulsing with warmth from both ends. Another impulse rolled through Ratchet’s sensory net, ringing pleasantly and loosening something deep inside in a quiet surge of delight.
He swore under his breath. Optimus always did this. Whenever they were alone, he tried to coax Ratchet’s softer side to the surface. And no matter how guarded the medic remained, Optimus managed to pull it off again and again with disarming ease.
“What kind of absurd question is that?” Ratchet protested, defensive out of long habit. It was the perfect moment for a proper counterattack. He stepped closer, wrapped one arm firmly around his sparkmate’s narrow waist, and, lowering his voice, finished:
“Of course I would.”
“I never lose hope that one day I might be given such an opportunity,” Optimus replied without a trace of irony, letting his own EM-field — hot with an unfulfilled need — wash over the medic.
It was easy to walk beside him in comfortable silence, surrounded by the dark, utterly deserted forest. A breeze rustled through the treetops, branches creaking softly. The heavy footsteps of the two Cybertronians seemed lighter, muffled by fallen leaves. Ratchet had to admit, the slow walk was doing his overworked emotional processors good. Venting with quiet satisfaction, he rolled his shoulders as he moved. He really should leave the base more often.
“We’ll need to watch our step now,” Optimus noted when a clearing appeared ahead.
“Mm?” the medic replied, reluctantly pulling himself from the blissful emptiness in his processor.
“The ground in this area is unstable, and the magma layers lie close to the surface.”
“I take it back,” Ratchet muttered as they reached the edge of the forest and stopped. “You’re not trying to kidnap me — you’re leading me into some elaborate trap.”
Optimus smiled softly, and his engine gave a low, devastatingly gentle rumble.
“It’s not a trap, my friend.”
But the landscape that opened before Ratchet’s optics looked very much like one. The clearing stretched for a good two hundred yards — an oval depression completely devoid of trees, at the center of which lay a perfectly smooth mirror of water. Even in the sparse night lighting, the lake remained a piercing blue, fading to yellow near the edges. And to top it off, a white blanket of steam curled above the surface.
“Oh? Then what is it?”
“Humans call this place the Grand Prismatic Spring,” Optimus said, straightening slowly and clasping his hands behind his back as he took in the view with quiet satisfaction. “Because of the nearby magma deposits, the water temperature here reaches eighty degrees Celsius.”
“Hm. I suppose that means most bacteria and simple microorganisms can’t survive here…”
Ratchet stepped a couple of paces closer, clearly intrigued. Organic residue in most naturally occurring liquids on this planet had been a constant headache in his processor. It clung to armor and joint casings, triggered corrosion manifests, and generally fouled up plating. After plenty of trial and error, he had managed to rig a semi-functional purification unit back at the base — but let anyone get caught in the rain, and their distilled water reserves dropped fast.
“There are a few species of thermophilic bacteria living here,” Optimus said, following him. “But only near the edges, where the water temperature is lower.”
He noticed the way the antennae on his sparkmate’s backpack assembly trembled with excitement, the subtle shifts in his armor. Then Ratchet cast a cautious glance over his shoulder.
“And how deep is it?”
Prime lifted his optics slightly, as if recalling something he’d read. The medic smirked,
“Oh come on. I already know you went in.”
“The soil structure prevented me from reaching the center,” Optimus admitted, “but about fifty yards out, it was roughly this deep.” He placed the edge of one hand across the middle of his abdominal plating.
“Oh, Primus…”
An entire lake of hot, relatively clean water, nearly shoulder-deep on him… Ratchet’s hydraulics itched with anticipation. It was incredibly tempting. Naturally, Optimus caught the surge of impatience in his field. He reached out, took Ratchet’s servo, and suggested,
“Come on.”
“No humans around?” Ratchet asked warily, scanning the area again.
“They visit during the day. At night, entry to the park is prohibited — but my long-range scanners are active,” Optimus assured him.
As they approached the water’s edge, Optimus turned and began walking backward, gently and confidently drawing his partner along. The bond smoldered with tender excitement. Tearing his gaze away from the water and the drifting white steam, Ratchet looked into Optimus’s optics — and faltered mid-step.
In the calm, content expression on his faceplate, in the warm brush of his EM-field, in the faint tremor of his digits — in every line of his frame — Ratchet could see who Prime had once been. The one who could look at his sparkmate with open, reverent adoration, without fear or restraint.
“Stop it,” Ratchet said abruptly, closing the distance as if trying to escape that look, gently pushing Optimus’s helm aside. “Don’t look at me like that.”
Prime only gave a quiet huff of amusement, his EM-field flickering in silent refusal as he tightened his grip on Ratchet’s digits.
The water truly was warm. What would have boiled a human alive felt just right to a Cybertronian. They moved slowly so as not to disturb the thin crust of earth beneath them, and the water gradually rose. Warm liquid flowed around their pedes and ankles, then their shins, filling evenly between heavy struts and knee joints. For the first few minutes, Ratchet’s HUD flashed uneasy warnings about rising system temperatures, but the levels never reached anything critical.
“Wait,” Ratchet said when the water reached the middle of his chestplate, tugging his partner’s servo.
He vented heavily, most of his intake grilles closed. Optimus stopped at once, optic ridges lifting with concern. The water barely reached his upper thighs.
“Are you alright?”
“Yes,” Ratchet nodded, clearing the warnings from his HUD. “It’s just… It’s been a long time since I felt something like this. Can we… stay here a while?”
“Of course,” Optimus replied gently.
He stepped back, giving Ratchet room to wrap both arms firmly around his waist and gain a steadier point of balance. Carefully resting his helm against the windshield, now pearled with fine droplets of condensation, Ratchet vented quietly for a while, acclimating to sensations he had almost forgotten. With a gentleness that seemed almost comical for his size, Optimus supported him by the shoulders. The warmth was soothing; drowsiness tugged at him again, pulling him toward hibernation.
“Feels like my frame might come apart into separate components,” the medic murmured without opening his optics.
“Similar to an oil bath, isn’t it?” Optimus agreed softly.
“Don’t remind me,” Ratchet huffed, pressing closer. His fingers drifted along his sparkmate’s back before curling around the base of one exhaust stack.
His audiosensor, still resting against Prime’s chestplate, picked up the way the gentle hum of the Spark deepened, how cooling systems clicked into a new cycle. A familiar yet rare sound — Optimus was laughing, silently and fondly.
“I have a suggestion…” he said after a pause.
In the end, they settled in the shallows, positioned so the hot water flowed lazily over their frames, lulling and loosening every joint and strut. Ratchet dimmed his optics, resting his helm comfortably on his sparkmate’s propped arm, and for a while simply listened to the steady hum of his systems.
“You know, Optimus,” he murmured after a long silence, “night shifts are technically meant for scheduled equipment maintenance. So I’ll have to take a couple of extra ones in the next few days.”
Optimus gave a barely audible engine-grumble. He shifted up on one elbow, slid his free hand across the medic’s chest, and, finding Ratchet’s servos resting against his radiator grille beneath the water, gave them a gentle squeeze.
“That may be true, my friend. But sometimes the one who maintains the equipment requires preventative care as well. As a result, the number of your night shifts will inevitably decrease.”
“Hmph.” Ratchet made a token grumpy motion with his helm, only to melt again into the soft waves of his sparkmate’s EM-field. After a heavy vent, he added gruffly, “But… thank you. For this trip. I… really needed it.”
Prime leaned a little closer, his voice quieter than the whisper of the water.
“Then I’m glad I insisted.”
Ratchet muttered something under his breath. But then he slipped servo free from Optimus’s grasp and slowly intertwined his fingers with Optimus’s. The gesture told Optimus more than words ever could.
“Still,” the medic concluded, optics dimming again, “this is a completely improper use of night shifts.”
“Perhaps,” Optimus replied calmly, “but undeniably the most effective one.”
Ratchet let out a rough chuckle, and the water around them trembled, rippling outward in gentle waves.