During the twenty-third century, the mixture of chemicals and gases in the air is so strange something amazing happens. There is a chemical reaction with the blood cells in human beings which creates reason for a match; there is one individual, from anywhere in the world, who fits another single person perfectly, and the effect is mutual. These people will be tied together for life in a relationship that can never fail.

Laboratories dedicated to studying the phenomenon rise up over the world; Beijing, Los Angeles, London, Cape Town, Rio de Janeiro, Lisbon, Seoul. Fifty years later, when the scientists think they understand how the blood bond affects personality and relationships, information is shared with the public about how to discover who your blood match is. Each person only has one blood match. They will never again have another, because that person is the person for them; the one person who is absolutely right for them in every way.

With this knowledge, agencies for discovering these blood matches pop up all over the world, though in public they use the term thought up by romance novelists over two hundred years before; soulmates.

---

Kim Joonmyun, just twenty-seven, runs Other Heart, Seoul’s biggest, best, and most famous soulmate agency. He’s been in charge of it for three years, since he graduated from university with a Master of Business.

Every day, except for Sunday, when they’re closed, tons of people from all over Korea, and some from further afield, come to the agency to be tested.

The testing process is relatively simple. A finger is pricked, the blood tested to find if there is a match in the system already. The computer is connected to an online document, and every person who has ever been to any soulmate agency is logged in this, until they find a match, and their information is removed. If there is a match, it will be able to find it.

Whilst the computer searches through the millions of people in the system, the customer is given a survey-slash-questionnaire to fill in. This is more for show than anything else, as the computer mostly does all the work. But if a match cannot be found due to the other person not yet being in the system, the questionnaire also gets inputted into the computer and can be used to help with matches. There are also people who refuse to have their blood taken, and the questionnaires can sometimes help with those cases. But most people are inputted into the blood matches system.

Unlike every other agency owner in the world, Joonmyun is single, because he hasn’t followed through with the processes himself. He’s just not interested. Helping others find their future loves, in the initial process and then helping them actually find where the person lives and contacting them, takes up all of his time, and he loves it. He doesn’t need a partner himself.

There’s a small part of him that says that his blood match probably wants to find him, but he never focuses on it for long.

---

The Beginning

When Joonmyun first started Other Heart, he’d been the only person there. He’d had access to the meagre system at the time, with the one computer he could afford after the costs of creating his business.

He’d had friends in university, and had invited them to test his company, but most of them had been too busy to come.

The first person to come was Wu Yifan, Joonmyun’s best friend. He’d come two days after opening, when Joonmyun was watching some terrible dating programme from 200-years prior on the Flashback TV Channel.

“Hi,” Yifan said, leaning over the counter. Joonmyun jerked his head away from the television and turned to face him with a smile.

Yifan had never really been one for dating during university. He’d been more focused on basketball and studying. He was a handsome man, one who many of Joonmyun’s friends, and multiple strangers, had had crushes on, but he’d just never gone for any of them. It surprised Joonmyun to see Yifan there. He’d only given the offer as a formality.

“My mother wants me married,” Yifan explained with a roll of his eyes, even though he was only just twenty-four years old. “I thought that maybe it’s time, after all.”

After he’d paid the fee, Joonmyun led the other man over to the system and went through the steps in his head quickly. Needle prick, drip into glass testing tube, tube into the computer’s blood hole (a section in the back of it for blood match testing).

He handed the paperwork over to Yifan to fill in before they start, and then filled in everything in the document, copying Yifan’s neat handwriting. Then he pricked Yifan’s finger, covering it with a plaster afterwards, and the computer got to work.

The two of them chatted about life in general as Yifan went over the questionnaire, but were stopped by the machine beeping loudly, the sign it had found a match.

Joonmyun stood excitedly, clicking open the document on the computer, and Yifan’s eyes widened with excitement. His knee bobbed on the ground.

“It’s exciting, isn’t it?” Joonmyun said, smiling widely.

“Yeah—I thought I’d have to come back. I never realised it’d be so fast.”

Then the match was before them. He clicked open the string of coded numbers, decoding them into text.

“Liu, Amber Josephine,” Joonmyun read aloud. “Twenty-two, Taiwanese. Lives in California.” There was no more information than that, just a picture and her email address. He showed it to Yifan; a girl with short hair, a wide, toothy smile on her face. Yifan nodded with a small smile on his face.

It was the other side of the world, California, but Joonmyun knew that distance would never stop a blood match from being made real.

He allowed Yifan use of the computer to send an email to his match, introducing himself to her, and moved back to his television.

His first match. He’d matched his first customer.

There had been something singing in his veins at the joy of it.

He remained involved in Yifan and Amber’s relationship. He heard when they first met, Amber flying over to Korea to see Yifan. He heard the stories, how much in common they had, how much Yifan liked her. And when, only six months after they’d met, they got married, Joonmyun was there as Yifan’s best man.

Yifan had told people he worked with about how everything worked, and quickly Joonmyun had other customers. By the end of his first month he’d successfully matched fifty people, and twenty had been inputted into the system for later matches.

He was later invited to every single wedding which resulted, a fact that never lessened during his later years working there. He was always invited to the wedding.

He soon had so many customers, as word of mouth was faster than anything he could compete with, that he needed to hire employees and buy a new computer (the computer came first).

He posted signs outside the building and in the newspaper, and soon had three offers.

The first was a twenty-two year old called Byun Baekhyun who seemed amiable enough, if his eyeliner-lined eyes weren’t a bit cheeky and full of mirth. He was just finishing college and had plenty of time, he said.

The second was a twenty-year old girl called Choi Jinri who was so pretty, her hair cut to her shoulders and her eyes wide and attractive, that Joonmyun thought she might be a distraction. If not to the customers, she would be certainly to himself.

The third and final person was an older man Joonmyun knew from high school, Cho Kyuhyun. They had been friends when Kyuhyun was in his final year and though Joonmyun wanted to hire him, he knew he couldn’t be biased, especially as he didn’t think Kyuhyun really wanted to work there.

He ended up hiring Baekhyun.

The first day at work, Joonmyun sat Baekhyun down before opening and went through the process of blood matching with him. He taught him what to say to the customers. Then he asked if Baekhyun wanted to be blood matched.

He jumped at the chance to do it for free, and they ran through the system, Baekhyun scribbling down answers in the new questionnaire Joonmyun had made.

There was no beep. Match not found, came up on the screen. Baekhyun’s smile dropped.

“It’s okay,” Joonmyun tried to reassure him. “I’m sure it’ll happen soon.”

Baekhyun gave him a small smile and Joonmyun went to open up, hoping that the day would cheer him up.

Baekhyun was a rather quite decent employee. He was never late, he was friendly, and he was rather good at charming the customers if it was a busy day. Joonmyun was grateful for his assistance.

On slow days Baekhyun would sing the Nation’s Girl Group So Nyeo Shi Dae songs as he watched their television performances. He seemed to like the leader of the group, Taeyeon, a lot, and he’d tell Joonmyun lots of things about her.

Since blood matches had happened, idol fan culture had relaxed a great deal. Although people had used to want to date their idols, they knew now that there was a very slim chance of that happening. This meant that the companies relaxed their hold on idols. If need be, they could date and marry—because it was inevitable, with the blood matches.

This didn’t stop some people, like Baekhyun, from dreaming about it. As long as Taeyeon was single, he’d pray for her to be his match.

Joonmyun almost wished she was, just so he’d settle down.

---

The company had been open for nearly a year when Kyuhyun came back in, this time not asking for a job.

“My Noona found her blood match earlier in the year and got married, so now I’m some kind of disappointment,” Kyuhyun said with a sigh, rolling his eyes.

This one’s quick. Kyuhyun was easy to input into the system, and it found a match within a couple of minutes; the fastest Joonmyun had ever seen.

“Okay, here we are,” he said, clicking on it. “Cho Jinho—”

He didn’t get to continue, because Kyuhyun groaned really loudly and dropped his head onto the computer desk.

“Oh man,” Kyuhyun said, muffled.

“What’s wrong?” Joonmyun asked him, frowning. Nobody had ever disliked their match before.

Kyuhyun pulled himself up from the desk slowly and looked at Joonmyun with somewhat pitiful eyes. “Could you do it again? Is there a chance something—?” He sighed as Joonmyun shook his head. “I used to babysit him, when we were little. Our mothers are friends, and I’m only a few years older, and he’s like a cute little brother to me, and I should have known this would happen.” He grabbed at his hair and ruffled it, messing it up, like a small child having temper tantrum. He dropped his head back onto the table. “Can I pretend it never happened?”

Joonmyun smiled and shook his head. “Hyung, you have to face this. You might realise you like him.”

“I guess my mother should stop hoping for grandchildren from me, then,” Kyuhyun muttered. “Thanks, anyway, Joon,” he added, and then left.

Joonmyun hoped he wouldn’t get any more people who didn’t like their match.

---

But of course nothing went Joonmyun’s way. In the next month he gained Krystal Jung, the younger sister of one of the members of Baekhyun’s favourite girl group, a girl with a boyfriend who ended up getting her boyfriend’s best friend Kim Jonghyun, a fact which both she and Choi Minho, her boyfriend, were horrified by.

After Krystal came Baekhyun’s best friend Chanyeol, who came over each day for a week to complain about his new college-aged colleague who seemed to like nothing more than to piss him off. It took another week to convince him to try for a match.

“I hope I get someone hot,” Chanyeol grumbled as the machine looked for his blood match.

It beeped after a long few minutes, and Baekhyun opened the document, Joonmyun over by the entry desk, and Baekhyun positively howled with laughter.

“You’re not going to like this,” Baekhyun said, and covered his mouth with his hand, trying to keep the laughter in.

Chanyeol grimaced. “What do you mean?”

“Well, they’re hot,” Baekhyun said. “That’s…that’s your only perk.”

Joonmyun, intrigued, crossed into the side room where they were and peeked over Baekhyun’s shoulder. Huang, Zitao, twenty-two, Chinese, lives in Seoul. The picture was small, attractive. For a moment he didn’t see why Baekhyun found it so funny, until he realised that Chanyeol may have mentioned his least favourite person was called Tao, and he got it.

“Oh,” he said, and clapped his hand over his own mouth, trying not to laugh in front of a customer. He had to run back into the main room before he burst into giggles.

Chanyeol seemed annoyed when he asked, “Why are you and Joonmyun-hyung laughing? Show me.” He stood up and walked around, and then stopped, and swore loudly. “.”

“I guess you and your colleague are going to get very close, very soon,” Baekhyun said, and Joonmyun could hear the smack Chanyeol gave him echoing throughout the building.

The fourth unhappy couple came at the end of the week, when two girls wrapped up in winter clothing came into the building together. They unwrapped themselves from the scarves, revealing themselves to be two members of Baekhyun’s favourite girl group, though Joonmyun was almost grateful they weren’t Taeyeon.

Baekhyun still looked a little freaked out as he took Im Yoona into the first testing room and Joonmyun took Kwon Yuri into the other.

Yoona was done first, the system not finding a match for her, and she stood in the doorway as Yuri finished hers.

The machine beeped.

Joonmyun felt a very strong sense of dread when he opened the match to discover Im Yoona.

Needless to say, the girls were not very happy, even if it was not his fault. That was the way the machine worked. It gave you the perfect match, without regards for gender, , personality—or whether they were your colleague or band mate. There was truly nothing he could do.

He did understand their reluctance to give him a good review, though.

---

Joonmyun’s next employee, another half a year later, was easy to pick. He knew instantly who it was going to be, and hired Park Sunyoung, a young twenty-two year old with smiling eyes and a gentle personality, on the spot.

When he offered her the test, she laughed, a pleasant, twinkling sound, and told him she was already bonded and married.

“Lee Jinki,” she said, showing him her ring. “One year in January.”

He was pleased for her, but he could tell Baekhyun was terribly jealous. He’d been rechecking for matches every month since he’d joined, but couldn’t find anyone. Joonmyun knew it must be upsetting for him.

Sunyoung’s first important customer came in a month after she started. The moment Joonmyun realised who it was, her manager trailing after her, he hurried Baekhyun into a side room and gave him paperwork to sort out, hurrying back in time to see Sunyoung hurry Kim Taeyeon into the other room and shut the door.

It was a few minutes later when Sunyoung left the room with a surprised look on her face. “Oppa,” she said, which was a good way of showing how frazzled she was—she wasn’t calling him Boss. “Oppa, come and see who Taeyeon-sshi got, you will never believe it.”

He followed her through to the room, nodding to Taeyeon politely, and then he stared at the name on the screen.

And stared.

And stared.

Because, somehow, quite unfathomably, the name Byun Baekhyun was sitting there on the screen, quite innocuously.

“Do you think he hacked it?” Sunyoung asked, biting her lip.

Joonmyun shook his head. “It’s impossible to hack.”

Taeyeon coughed then, tapping her foot on the ground impatiently. “What’s wrong?” she asked. “Who is it?”

“It’s…” Joonmyun blinked, trying to phrase it in a good way.

“It’s our other colleague,” Sunyoung said. “Byun Baekhyun.”

Taeyeon looked surprised, as if she were expecting someone else.

“Would you like to meet him?” Joonmyun asked, although he wasn’t quite sure it was a good idea.

She nodded, though, so he led her out and to the other room.

“Baekhyun,” Joonmyun said, popping his head around the door. “So you might have a match, but you’re not allowed to freak out. Promise me you won’t.”

Baekhyun nodded his head, looking confused, and then his eyes widened almost comically when Taeyeon went to sit down next to him.

“Hi, I’m Taeyeon,” she said. “I guess we’ll be learning lots more about each other very soon.”

Baekhyun could only make squeaking noises in response.

Joonmyun wasn’t surprised. It wasn’t every day you not only met your idol but discovered they were your blood match, your life partner.

It almost made him want a match of his own, but not really.

---

During the following year, many of Joonmyun’s friends and customers got married or had children. Amber and Yifan had twins; Jacqueline and Kevin. Kyuhyun and Jinho seemed to have got along much better than Kyuhyun had predicted and they invited Joonmyun to the wedding. Jinho was a boy shorter than even Joonmyun with puffy cheeks and the world’s most adoring expression when he looked at Kyuhyun, and Kyuhyun wasn’t much better off. Krystal and Jonghyun, having put aside their differences, married as well—a shotgun wedding, as Krystal was two months pregnant. Even Chanyeol and Zitao seemed to have settled into some form of comfortably dating, if the kiss Zitao had given Chanyeol when he dropped him off a few weeks before was anything to go by.

Baekhyun and Taeyeon got married at the end of the year, and there was a huge celebrity wedding with the rest of Taeyeon’s group members, including Yoona and Yuri who were subtly holding hands. Baekhyun had fallen harder for Taeyeon every day he was at work and Joonmyun thought it was very romantic.

One day a young-looking boy with blond hair rushed in with a chubby cheeked boy behind him. “I’m here to be tested,” the blond boy said. “Minseok’s keeping me company. I’ve never done this before.”

Joonmyun took the boy, Lu Han, older than he looked, through to one of the side rooms and they began.

After a few moments, the machine gave a match.

“Kim Minseok,” Joonmyun began, and Lu Han shrieked, leapt to his feet, and threw himself at his friend, kissing him smartly on the mouth.

“I have wanted to do that for months,” Lu Han said, smiling. “I’m so glad it’s you.”

Minseok wrapped his arms around Lu Han’s waist and kissed him back, and Joonmyun felt something swell in his heart.

They got married only a week later, and Joonmyun almost cried at the wedding, though he wasn’t really sure why.

Once wedding season was over, he was back to matches. Seo Juhyun and Henry Lau in Canada, Oh Sehun and Choi Jinri—the same one who had tried for a job—, Song Qian and Zhang Yixing in China.

It had reached the start of the third year of Other Heart, and Joonmyun celebrated with a third and final employee and computer. His employee this time was a friend of Baekhyun’s called Kim Jongin, and Joonmyun felt his heart swell uncomfortably when he looked at him—a feeling that got worse when the computer didn’t beep at the end of his test—, but he couldn’t take the offer back.

Jongin was even more diligent than Baekhyun, and quieter than Sunyoung, and better to look at than both of them, which made him an excellent addition to the team.

With his addition, we are brought back to the present.

---

The Present Day

Joonmyun avoids looking at Jongin as often as he can get away with. There’s something in him, when he looks at his youngest employee, twenty-three years old, that makes him want a blood match.

But Joonmyun’s been here too long. He doesn’t want one, really. He’s perfectly fine alone and dateless. He’s never had a boyfriend (or, indeed, a girlfriend) and he doesn’t intend to start now, at twenty-seven, running an incredibly successful business. He doesn’t have time for another person.

But several months after Jongin joined, when they’re tallying well over 600 matches, Jongin asks him why he’s not married.

“You’re the only blood matcher in the world who isn’t married,” Jongin says. “It was on the news. They were saying we should force you because your future love probably wants to meet you, but you won’t.”

“I don’t have time for a relationship, Jongin,” Joonmyun says. “I’ve been running Other Heart for three years now, going on four. I don’t need a relationship.”

“But that’s selfish, Hyung,” Jongin says. “I’ve wanted to know who my blood match is for months, and they’re still not in the system. What if they’re like you and they don’t want to know? I could end up single forever, and that would , watching all my friends get married whilst I can’t. If your future wife, husband, whoever, wants to meet you—” He shakes his head. “The least you should do is put yourself in the system.”

Joonmyun’s avoided the needling of Yifan, Kyuhyun, Baekhyun and Sunyoung, but somehow he can’t dodge Jongin’s words, and he finds himself in the chair with Jongin running him through everything, pricking his finger and sliding the tube into the computer.

Joonmyun hopes that he won’t have a match, but he’s never lucky.

The machine beeps, and Joonmyun keeps himself in his chair. He doesn’t care. He doesn’t care.

Jongin freezes.

This jerks Joonmyun out of his stupor and he frowns. “Jongin?” he prompts. What name could have got Jongin into such a state?

“Yes,” Jongin says, but it’s not a question. He’s not prompting Joonmyun. He’s—“Yes,” he repeats. “Exactly.”

Joonmyun feels bubbles of fire in his veins and he’s out of his chair and behind Jongin before he even realises he’s moving, and sure enough; Kim, Jongin, twenty-three, Korean, lives in Seoul.

He has to grip onto Jongin’s chair tightly or risk collapsing.

“I—I’m sorry,” he says, instead, although he’s not sure if he’s apologising for it being him, or for taking so long about it.

Jongin shakes his head, and closes the computer session. “At least I know,” he says. “I only wanted to know.”

And then he walks out of there and into the main room of the building, leaving Joonmyun behind, still unsure of what to think.

---

They’re awkward with each other, after their discovery. Sunyoung’s the first to point it out.

“What’s wrong with you and Jongin, Boss?”

Joonmyun shrugs. “I’d rather not talk about it,” he says, and she lets it drop, for the moment.

A few days later, Baekhyun says to the both of them, “Jongin’s found a match, but he won’t say who it is.”

“How do you know?” Sunyoung asks. Joonmyun keeps his mouth shut.

“Today’s the day he always tests himself, but he hasn’t yet. And when I asked, he said he doesn’t need to anymore. Boss, do you know anything?”

Joonmyun turns pink, and shakes his head. “Let’s get back to work,” he says, and heads back to his desk. It’s a quiet day, and work, in his case, means watch more 200-year old dating shows, much to Baekhyun’s disgust.

He gets a few days of respite, and then Baekhyun lets out a loud, “Got it! Sunyoung!”

Sunyoung runs through quickly.

“What have you got?” Joonmyun asks, without really caring.

“I’ve got the record that got Jongin’s name. It took me a few days to find it, but it’s coming up with a name now.”

Joonmyun feels the hairs on the back of his neck bristle. “You shouldn’t do that!” he exclaims as he runs through to the room Baekhyun’s in. “It’s personal, it’s wrong, it’s private—”

And there’s his name on the screen. Kim, Joonmyun, twenty-seven, Korean, lives in Seoul.

Baekhyun and Sunyoung turn slowly to face him and Joonmyun just stands there, biting his lip.

“Boss, you never said you got tested,” Sunyoung says, breaking the silence first.

“I didn’t want to,” Joonmyun says softly. “Jongin forced me to do it.”

Sunyoung sighs, looking at the page. “At least we know why it’s so awkward around here.”

“Believe me, I never wanted this to happen,” Joonmyun says. “I like Jongin, a lot, so it’d just be—”

Baekhyun grins, and Joonmyun realises it came out like a confession.

“No! I mean he’s a good worker, I—” He shakes his head. “I don’t—”

But he can’t really lie to himself. He likes Jongin, and it’s almost worse that he and Jongin are blood matches, because he has to like him. He wants Jongin to like him, too, but knows that may not happen for a long time.

And then there’s an arm going around his waist. “You found out?” Jongin asks, and he sighs. “I wanted to tell you properly.”

“Sorry,” Baekhyun says, although he doesn’t look sorry. “You look cute together.”

Joonmyun turns pink, and Jongin laughs. “I guess so,” he says. “Maybe we should take a picture.”

Everything is so strange that Joonmyun doesn’t know what to do when Jongin drags him out of the room and into another one. “Hyung,” he says, “do you want to go out with me? I’ve been thinking for days about this and, and I think we can make it work. Blood matches never break up. We can work together and still be fine, and you’ll have time for work and for me.”

Joonmyun can’t deny that it sounds appealing. “Okay,” he breathes, although he still feels awkward about it. He also can’t believe that Jongin likes him already. “Let’s try.”

“Can I try something else?” Jongin asks in a whisper this time, moving a little closer, and Joonmyun nods and shuts his eyes as Jongin’s lips brush against his.

It feels so wrong to be kissing his employee whilst they’re at work, but at the same time the other two are married, so he doesn’t really care what they think.

He kisses back.

---

The Future

After a long time of casual dating; dates in the evenings or Sundays, quick kisses at work, Joonmyun gets up the courage to ask Jongin to move in with him, knowing that his house is bigger.

Jongin doesn’t protest, and soon they’re sharing a bed more than once a week. Waking up to Jongin is one of the best things Joonmyun could have ever known.

Baekhyun and Sunyoung still tease them about their relationship, about when they’re getting married, about when they’re having children. By this point both Sunyoung and Taeyeon are heavily pregnant and it’s all rather exciting. Joonmyun mumbles something about cats, because aside from orphans, whose parents have died, there are no children to adopt anymore. Joonmyun would love to adopt, if he’s honest, but he doesn’t know what Jongin thinks.

When he mentions it later, Jongin kisses him and tells him he wouldn’t mind.

They get married a year after they met. All of Joonmyun and Jongin’s friends come. Joonmyun’s all crowd around and tell him it was about time.

“I can’t believe it took until you were twenty-eight,” Yifan says. Joonmyun hits him, but there’s no malice in it.

Once they’re married, there’s nothing stopping them.

Joonmyun feels like he’s flying, and his company is soaring with him.

Nothing could be better.