Every day I did my level best not to break any dragon eggs on the way into work. Build-A-Dragon's headquarters were in downtown Phoenix, a slab of volcanic glass amid the grays and browns of the Sonoran desert. I usually rode the elevator up to the seventh floor and took a shortcut through the Hatchery. Warm air spilled out when I pulled open the door, carrying with it the buzz of activity. Dozens of white-garbed staffers crowded the hallway between the pods. Aluminum egg carts glided back and forth with their precious cargo. I took a breath and plunged into the obstacle course.

The hatchers didn't make it easy. When they had an egg in their possession, other humans might as well not exist. I had to skirt and dodge around three pairs to reach the door to the design lab.

Entering the cooler, darker space always relaxed me from the chaotic hatchery crossing. The hum and whine of the God Machine—our biological egg-printer—provided its own sort of white noise. Like the sound of crickets in the desert at night. I knew right away something was different today. My boss Evelyn stood by Wong's workstation; the two of them spoke in hushed voices. It sounded like the lilting rise and fall of Mandarin, though they didn't usually speak it at work unless they were humoring my attempts to learn.

"Hey guys," I said. "What's going on?"

"We have a meeting this morning," Evelyn said.

"A lab meeting?" I suppressed a groan. We never had a lab meeting unless something big was happening.

Wong shook his head. "Marketing meeting."

Strange. The people in marketing rarely spent time with designers. "Okay. What time?"

"At ten," Evelyn said. "They're coming down here."

"Something tells me I'm going to need caffeine for this." I dropped off my bag at my workstation and made a beeline for the coffee bar.

Right at ten o'clock, Tara and Cynthia—the women who co-directed Build-A-Dragon's marketing department—arrived on the design floor with an entourage in tow. Work screeched to a halt at the procession of blonde hair and Calvin Klein suits. I scurried out from behind my desk and followed the lingering current of perfume to Evelyn's office. Wong appeared right beside me. The bemused smile on his face that said he knew just as little about this as I did.

He and I took the hastily-erected folding chairs at the foot of Evelyn's glass table-desk. My chair made a high-pitched squeak as I sat down. Wong's quivered like it might collapse beneath him. Meanwhile, Tara and Cynthia floated like swans to the two plush leather chairs facing Evelyn's. The members of their entourage remained standing in a little clump behind them.

Once everyone settled in, Evelyn put on a big smile that looked painful. "So, how can the design team help marketing?"

"Well, we're very happy with the Rover model," Tara said.

"So happy," Cynthia agreed.

They'd better be happy with it, I couldn't help but thinking. The Rover was our first domesticated dragon, a replacement for the family dogs that had been virtually wiped out by the canine epidemic. According to Wong, who had friends in the Sales department, we had six months' of shipping receipts lined up, with no sign of slowing.

"We're glad," Evelyn said carefully.

"But we also think a few tweaks could make a big difference on the bottom line," Tara said.

"What do you have in mind?"

"Well, we're not sure the Rover models eat enough."

"They have no trouble maintaining weight," Evelyn said.

"If anything, they tend to get a little pudgy," I added. The overweight dragons were hardly a secret after that video with one stuck in the doggie door practically broke the internet.

"What if they could eat ten percent more?" Tara asked.

"Without getting fat," Cynthia said.

Evelyn looked thoughtful; I could tell she was already considering the metabolic changes. That was her pet research area. We all had one. Mine was neuromuscular function; Wong's was pigmentation.

"Why?" I asked.

"Most Build-A-Dragon customers buy their food from us," Tara said.

"And you want them to have to buy more of it."

"Exactly."

I should have seen that one coming. I opened my mouth to make a snarky comment, but closed it again. Instead, I looked at Evelyn.

She shrugged. "We can try making adjustments to the metabolism, but no promises."

"That would be great!" Tara said. "Now, let's talk coloring. What if the customers could order a Rover in any color they wanted?"

Wong had already implemented coloring and pigmentation sliders in our program, but we weren't about to volunteer that information. God knows what they'd ask for next.

To Evelyn's credit, she played it cool. "Now that I'm more confident we can do. In a matter of weeks."

"Wow! How fantastic." Tara smiled, and the brightness of her teeth was hard to miss. Still, something about it put me off. It was more predatory than inviting.

"Anything else?" Evelyn asked.

"Actually, I was hoping we could talk about the Courier."

That was our prototype messenger dragon, a small flying model that could carry a payload of about half a pound. Wong had designed it, but he was too polite to get his hackles up.

Luckily, I was there. "What about it?" I imagine I kept most of the defensiveness out of my voice.

"What's the life expectancy for that model?" Tara asked.

Evelyn deferred to Wong.

"Twelve years, based on simulator," he said.

"Could that be adjusted?" Cynthia asked.

I jumped in. "Life span takes feature points. We probably can't push it much longer."

Feature points were an intentional limitation of our dragon design protocols. Every advantage we gave them—intelligence, strength, wingspan, those sorts of things—required a certain number of points from a finite sum. I was always fighting it to give my dragons what they needed. I'd borrow from intelligence to boost metabolism, or sacrifice claw length for bigger teeth. I hated the points system. But the mandate came from the top, CEO Robert Greaves, and there was nothing a junior designer like me could do about it.

Cynthia winced. "Yeah, we're actually going to need you to shorten the lifespan."

"Why would we do that?"

Tara pulled up something on her tablet. "Here, look at this." She made a sliding motion, and projected an opaque square on Evelyn's wall. A line plot materialized there: annual sales versus dragon lifespan. The line sloped downward at a steep angle.

"The longer they live, the fewer dragons we'll sell, because they don't need replacing as often."

It rankled me how they talked about dragons—my dragons—as disposable things. And I was in a crabby mood, so I couldn't help myself. "Here's an idea. What if we have them drop dead every time they deliver a message?"

Evelyn's gave me a little head-shake but she was too late. Tara and Cynthia's faces lit up like Christmas trees.

Uh-oh. Here it came.

"Could you really do that?" Tara asked.

"I mean we probably could, but I'm not sure it's—" I started.

"Oh, that would be spectacular!" Cynthia turned to Tara, and they both started talking at once.

"Think of the market potential."

"What a killer angle, too!"

"What should we call it?"

"Dying dragon?"

"The last dragon?"

"No, too grim!"

"We'll think of something."

Finally, they seemed to realize how hard Evelyn, Wong, and I were trying not to roll our eyes.

"How soon can you design a prototype?" Cynthia asked.

"If it's possible, we'll have one in about a month." Evelyn raised her eyebrows at me, to make it clear that she meant the royal we.

In other words, me.

I sighed and shook my head while Tara, Cynthia, and their entourage made their exit, babbling excitedly about the prospects of a one-way dragon.

Aw hell, I just came up with the name for it, too.

#

Correcting the metabolism on the Rover model took me just over a week. I cared very little about selling more dragon food, but the Rover's metabolism still had some kinks to work out anyway. Part of the problem with weight gain was this: a Rover dragon would eat just about anything. Meat, grains, vegetables, you name it. We knew they'd end up collecting table scraps the way some dogs do. Their digestive systems handled it pretty damn well, all things considered. But no metabolism could defeat the high-fat, high-sugar diet of modern America. When a Rover ate what its owners did, it put on weight and got diabetes just like them.

Still, we couldn't knock down all of the digestive enzymes. A dragon that required specialized food wouldn't survive a week in most households. The more I looked at the Rover's metabolic system, the more I came to realize that we had very little room to operate. The design team had already maxed out every gene for fat breakdown and protein digestion. I mean every one I could think of, and some I had to look up. I sensed Evelyn's hand in that.

Then I remembered a lecture from graduate school about genetic responses to a fast-food diet. Some of the variation in response arose from the animal genetics; no one disputed that. But the microbiome—the bacteria and micro-organisms that lived inside and on our bodies—played a role, too. Efficient microbes helped the gut extract more sugars and carbohydrates from ingested foods. Less efficient microbes did just the opposite, which meant the host could eat more without absorbing excess calories.

That's when the idea hit me. I double-checked it against the latest set of research on the microbiome. Then I practically ran to Evelyn's office. "I think I've got a fix for the Rover metabolism."

"A microbiome alteration?"

"Argh!" I pointed an accusing finger at her. "You already knew, didn't you?"

She shrugged. "It makes sense. We can only do so much with the dragon genome."

Sometimes I forgot that Evelyn practically wrote the book on genetic engineering. "Well, here's the best part. If we find the right microbial combination, we can retroactively treat all the Rovers we've sold already."

Her eyes widened. "Now there's an idea I didn't think of. How would we deliver it? A special supplement?"

"Or, we just lace next month's food with it, and then re-brand as 'Now with pro-biotics.'"

"Have you been spending time down in marketing?"

I grinned. "I wish!"

"I'll pitch it to the board this afternoon. Great work."

"Thanks."

"Now you can tackle the new design."

The one-way. "I was kind of hoping that idea died in committee."

"Whose idea was it again?" she asked.

I sighed. "Mine."

"And now you get to work on it."

"I was making a joke! Don't you object to the idea of creating a dragon that has to die?"

"We breed research animals that are going to die. And cows and pigs that are going to be eaten."

"That's different," I said. "That's about survival."

"So is this. If this company doesn't keep selling dragons, it won't last."

"But do we have to design this dragon? It feels wrong."

Evelyn smiled. "Think how much you will impress the ladies in marketing."

That was clever of her. Now that I thought about it, I probably wouldn't mind impressing them. They were women, after all. But they were also way out of my league. "Yeah, I don't think that's going to happen."

"Robert loves the idea, and went so far as to ask me who's working on it."

Crap. She meant Robert Greaves, the CEO. Someone whose good side I wanted to be on. "Please tell me you said Wong."

She shook her head. "It was your idea."

The guilt hadn't gone away, but there was a certain allure to a hard scientific problem. I couldn't deny it. Besides, the company needed business and I needed the company. I just know I'm going to regret this. "All right, I'll give it a shot."

"Make sure it's your best shot, Noah Parker."

#

The ageing process happens in all animals. Humans have sought ways to reverse it for hundreds of years. The rise of genetic engineering reinvigorated the search for a Fountain of Youth and focused it on the bases that made up our genome. Although immortality was well beyond our grasp, researchers had identified dozens of genes with minor effects on longevity. The right combination of those could extend an animal's lifespan by ten or twenty percent.

Or, with the opposite tweaks, I could take it away. I felt bad, but Evelyn had challenged me to find a way to make it work. The need to impress her still drove me, still fueled my ambition to excel. Some day she might move up in the company hierarchy, and I fully intended to be next in line for her chair when that happened.

I trudged back to my workstation and pulled up the current Courier model in my simulator. Wong and I designed the original prototype. We wanted to call it the Parkong, an amalgamation of our last names, but the marketing folks overruled us. They thought it sounded "more like a waterproof garment than a dragon."

So much for taking credit.

DragonDraft3D already had a slider for "Life Span" that I'd never used before. Now, I slid it down to the absolute minimum, which freed up some feature points that I could use on metabolic enhancements.

Then I ran the design through the biological simulator, which gave us a somewhat accurate prediction of the grown dragon's characteristics. It estimated the lifespan at around a month. I shook my head. "Not short enough."

Marketing's dynamic duo had sent down some notes from their early market research. Early adopters would likely use the one-ways within their home cities at first, to establish that it actually worked. In a decent-sized metropolis, a little flying dragon could probably cover most routes in a few hours.

If it died twenty-nine days later, that kind of defeated the point.

I tamped down the enzymes that eliminated free radicals and knocked out half of the master DNA repair proteins. Then, I went hunting for the handful of longevity markers I'd overlooked. I reversed their effects, and ran the simulation again. Now it estimated a lifespan of less than a day. Marketing ought to be thrilled. With the right life-shortening diet, these poor little flying lizards wouldn't last more than a few hours.

Evelyn materialized right after I'd made the final touches. "How is the prototype design looking?"

"Just about ready." I ran it through the simulator so she could have a look at the 3D rendering.

"Oh, very nice." She leaned close as the hologram twirled in slow motion. "It's leaner than our other fliers."

"Has to be," I said. "It's got the metabolism of a hummingbird. But it'll fly pretty well, I think."

"Can I see your list of modifications?"

I'd just pulled them up into a new window. She ran down the list. "A lot of longevity genes on here, good. Oh, and DNA repair?"

"A bit of insurance."

She pursed her lips.

"Something wrong?" I asked.

"No. It'll be interesting to see how these turn out, that's all."

I got the sense she was holding back further comment, but I also didn't care. The sooner this assignment was over with, the better. "Does that mean we can run a field trial?"

"Let's keep it small. Print four eggs."

"You got it." I hit the Print button before she could change her mind. The sooner we produced a viable prototype, the sooner I could move on from this cursed project.

#

We ran the field trial right from the Build-A-Dragon headquarters. Two hours before hatching time, four wranglers drove the eggs north, south, east, and west. Different neighborhoods, different distance. All of them had the same instructions for hatching the dragon, along with a message it would carry to Build-A-Dragon's headquarters. Marketing even developed a sleek little message tube that strapped to the dragon's torso.

Evelyn and I waited on the front steps, both of us pretending not to be nervous. I'd set my watch for when the eggs would hatch; that was half an hour ago.

We should have seen one by now.

I glanced at Evelyn and caught her checking her watch. "You timed the routes, didn't you?"

"What? Of course not."

"Me neither," I lied.

We stood and fidgeted for a few moments longer.

Finally, I threw in the towel. "The first one's late."

"By seven minutes," she said.

"Damn. You gave them the feeding instructions, right?" The hatchlings needed a high-protein, high-fat meal as soon as they broke out of the shell. It would both provide the energy to fly, and the free radicals to seal their early demise.

"Of course. These are Tom's best people."

"How is your handsome friend in Herpetology?" It was no secret that Evelyn had a minor crush on Tom Johnson, our consulting herpetologist. Not that I blamed her. The guy was a legend in his field and had personally captured half of the organisms whose genetic codes went into the dragon reference.

She blushed. "I don't know what you mean."

I cherished the rare sight of a flustered Evelyn Chang. She was right about one thing: she definitely shouldn't have brought him up.

A mud-spattered pickup veered off the main road onto Build-A-Dragon's circle drive. I mistook it for a lost tourist who'd made a wrong turn. It stopped near us, and a bearded guy in dungarees climbed out. One of our dragon wranglers, no doubt.

"You'll want to see this," he said.

Evelyn and I looked at each other, like, Is he talking to us? Wordlessly, we approached the pickup. The wrangler had gone around back and opened the tailgate. Inside lay a wrinkled, pitiful old dragon the size of a football. The thing had lost half its scales; the ribcage showed against its emaciated stomach.

"Oh my God," Evelyn said.

I bent closer to look at the little creature. The rheumy eyes and atrophied muscles made it the oldest dragon I'd ever seen. It must have been one of the early prototypes from before I joined the company. "Where did you find it?"

"I followed him for a couple of miles, until he couldn't fly anymore."

"What do you mean, you followed him?"

He slammed the tailgate back in place, nearly smashing my hand in the gap. "What do you mean, what do I mean?"

"I—" I began.

"I hatched him, fed him with my own hands," the wrangler said. "Then I watched him die."

Realization crept over me like a sudden chill. "This is one of our test dragons?" It didn't make any sense. The dilapidated reptile in front of me looked ancient. A couple of years old, minimum. I figured he'd found it alongside the road or something.

"Yeah. Here." He fished something out of his pocket and shoved it at me.

I found myself holding one of marketing's sleek message tubes. I blinked, hoping that it was a trick of the heat.

"Consider your message delivered." He climbed back into the truck and peeled off.

I turned to Evelyn. "Yikes."

"I don't think that was your best shot," she said.

#

The field test taught me two important things. First, a rapidly aging dragon made a poor courier. The initial feeding gave the hatchling an initial boost of energy and kicked off a metabolic chain reaction that sealed its doom. Only the wretched prototype I'd seen in the wrangler's pickup made it anywhere close to Build-A-Dragon's headquarters.

The field trial also taught me that I couldn't design every single dragon on my own. I hadn't foreseen the problems with the senescence model. Nor had my simulator. Build-A-Dragon employed some of the most talented genetic engineers in the world.

So, I swallowed my pride and leaned across the wall to Wong's workstation. "Hey Wong, you busy?"

He grinned, because I'd asked in Mandarin. I'd been teaching myself via podcast during my commute and he often bore the brunt of my conversation practice. "Oh, your Chinese is improving."

Liar. I switched back to English. "Could I ask your advice on a design?"

"Custom job?"

"No, a new prototype."

"Give me the specs." He leaned back in his chair and took a big bite of an apple. His third one of the day, by my count. The God Machine provided wonderful white noise, but when Andrew Wong ate an apple, the entire design lab heard every bite.

"Lightweight flying model. It has to carry a message in a kind of special tube."

"Sounds pretty standard." His eyes drifted back to his projection monitors.

"Oh, and it has to die after making delivery."

"What?"

"It's a one-way messenger dragon that marketing was all excited about."

"They really want it?"

I nodded. "And guess who gets to design it."

"You have my attention now, Noah Parker."

He and Evelyn both liked to use first and last names. Must have been a cultural thing. Not that I minded or anything—he made it sound a little bit like I was a superhero. We need your help, Noah Parker!

"I tried to accelerate senescence with free radicals and DNA damage," I said. "It wasn't pretty."

He shook his head. "Never going to work."

Well, sure, we know that now. "Yeah, the field trial was a disaster." I'd gotten the dying part right, but the message delivery, not so much.

"You need two parts. Trigger, and response." He punctuated each of these by thrusting the half-eaten apple in the air.

"Okay, what's the right trigger? When it hatches?" That moment would seal each dragon's fate. Born to die, you might say.

"Maybe. How long does it need to live?"

"See, that's the problem. It might be an hour, or it might be two weeks. Depends on how far away the recipient is."

"Then it happen at delivery."

"Like the recipient does something?" The idea tempted me, but any time we had to rely on the customers to do something—even a fundamental thing like read the damn manual—we set ourselves up for disappointment. I shook my head. "No, the trigger has to be intrinsic."

Wong waved me off. "You can figure it out. Then, we give it name."

"We tried that with Parkong. It didn't go well."

"I have a new one this time."

"Yeah?" I can't wait to hear this.

He grinned, and mimed spreading a banner out overhead. "Wonger."

I laughed, because it was hilarious but it was also never going to happen. "You know your name's pretty close to 'wrong', don't you?"

"Wong is opposite of wrong."

"Well, I'll let you bring it up to marketing."

I opened up my design and removed all of the senescence crap. Let's start with a good, clean flying dragon. All of the extra feature points went to strength and endurance. Then I looked up the neuro-pathways underlying satisfaction, searching for the right place to create a feedback loop. These already existed in the reptilian nervous system, but had failsafes to keep the signals in check. All I had to do was knock those out.

However, the problem with using satisfaction as a trigger emotion became obvious even before I made the changes: so many stimuli activated that pathway. Satisfaction was evolution's way of rewarding survival behavior. Food, sex, exercise, and half a dozen other stimuli might cross-react.

I ambled back to Wong's workstation. "I'm worried satisfaction is too broad."

"How about anger? We could make it the angry Wonger!"

"I never agreed to that name!"

"Your mouth says no, but your eyes say yes."

"Stop looking at my face, Wong."

"I'm trying to help you kill dragon."

"I don't want to have to kill them. It's just that I . . ." I trailed off with the familiar pang of regret. How did I get into this mess?

"Opened your mouth?" Wong offered.

"Exactly."

"So now you kill. Maybe you can be nice about it."

I harrumphed, but something about the way he phrased it made me think. Maybe there was a way to do right by these little dragons. "You just gave me an idea."

He was silent a moment, then leaned closer and lowered his voice. "Idea is . . . angry Wonger?"

I laughed again. "No! Go away now. I need to work."

#

Two weeks later, Evelyn and I met on the steps in front of Build-A-Dragon. I'd invited Wong to join us, both for moral support and as a nod toward his help on the design. Predictably, marketing shot down our proposal of "Wonger" for the model name. But when I floated them the idea of calling it the One-way, they bit like hungry sharks. Now all we need is for it to work.

"How long till we see one?" Wong asked.

I looked at Evelyn, who held up four fingers. "Less than five minutes," I said.

Neither Evelyn nor I brought up the previous trial. I kept fighting surges of panic that this one would yield the same result. Evelyn usually gave us a pass on the first disappointing field test for a new model, but if this one bombed she'd probably give the design to someone else. As much as I hated the concept of a disposable dragon, I didn't want to lose design rights. That counted against you in Evelyn's unofficial scorebook. As far as the design group was concerned, it was the only book that mattered.

I screw up enough, and I'll get bumped to junior varsity. Then I'd spend most of my time fielding support requests rather than designing new prototypes. Not quite a punishment, but close enough.

"Why so nervous?" Wong asked.

I rolled my shoulders. "I just want this to work."

"Relax, Noah Parker. You have Wong on your side. Look." He pointed over my shoulder.

Please, let it be. I turned around, scanning the horizon. A dark little dragon glided down the avenue toward us. It looped and danced through the maze of street signs and lamp posts.

"Wow," I whispered.

"Good agility," Evelyn said, sounding pleased.

I still didn't believe it, didn't accept that this was my newest prototype until it spotted us and swooped down. It landed on the concrete with an eagle's grace, met my eyes, and crooned at me.

A laugh burst out of me, and the tension drained from my shoulders. "Well, hello, little fella!"

I held out my arm and he fluttered up to land on it, light as a feather. I didn't even mind the way his talons poked into my forearm. I unscrewed the message tube from his leg and slid out the paper. "It's the Scottsdale prototype."

"Yes!" Wong pumped his fist.

Evelyn clapped her hands. "Twelve miles! He made good time."

"He sure did." I held him up. "Thanks, little buddy. Message received."

His pupils dilated, and he sighed. His eyes rolled back into his head. The claw that held my forearm went slack. I grabbed for him, but missed. He flopped to ground the like a rag doll.

We stood there in shocked silence for a moment. The dragon didn't so much as twitch.

"It worked," Evelyn said.

"Yeah." I felt an odd mix of shame and satisfaction.

"How did you do it?"

"A dopamine feedback loop."

"Dopamine?" She pondered this a second. "But what if the dragons find some other satisfaction before—"

I shook my head. "It only works for one stimulus."

"Which?"

"I think you can figure it out."

She pursed her lips, and I could almost hear her thoughts whirring. "It would have to be precise. Tied to the mission of delivery."

"They're given a single task to complete. And when they complete it . . ." I gestured at the fallen dragon.

"A sense of achievement. Pride."

"There you have it," I said.

"It's clever."

I shrugged. "Wong gave me the idea."

"Moment of pride, then death from pleasure," Wong said.

"It was the least I could do for them." I owed the dragons that much, especially after the miserable failure of the senescence prototypes.

"Nice touch." Evelyn gave me a side look. "I know you didn't like doing this."

I snorted. "Did you?"

"No, but—"

"But we do whatever it takes to keep the lights on." Build-A-Dragon needed to sell dragons. Otherwise it would fold, like most startups, and then no one would have them.

"Yes. Speaking of which, I was hoping you might take a look at the specs for a new prototype." She paused. "If it's too soon, I understand."

Yet another prototype. Part of me wanted to take a break, but the siren song of another scientific challenge called to me. "All right, send me the specs."

Her eyes sparkled with amusement. "I already did."

"Then I suppose I should get to work." I clapped Wong on the shoulder and headed back inside.

My name was Noah Parker, and I designed dragons.

Copyright © 2020 by Dan Koboldt

This story takes place in the world of January 2021 debut science fiction novel Domesticating Dragons by Dan Koboldt. As a genetics researcher, Dan Koboldt has coauthored more than 80 publications in Nature, Science, The New England Journal of Medicine, and other scientific journals. He is the editor of Putting the Science in Fiction from Writer’s Digest Books. Koboldt is an avid deer hunter and outdoorsman. He lives with his wife and children in Ohio, where the deer take their revenge by eating the flowers in his backyard. On his blog he runs the popular “Science in Sci-fi / Fact in Fantasy” series, where experts in various fields contribute articles about how to write more realistic fiction. He has written general science articles for Clarkesworld, Apex Magazine, and Baen.com.