The man drummed his fingers on his desk as he listened to the officers make their report. He sighed when they'd finished, a wriggle of displeasure worming its way down his spine.

Earlier in the week, the Security Bureau had received a ping about a citizen who had returned from her study abroad program early. It wasn't an issue at first. Her grandmother had passed, and so they only kept tabs, thinking she would go back to No. 5 when the funeral and cremation was taken care of. The girl, however, terminated her study abroad abruptly and started buying up suspicious travel supplies and consorting with surveilled persons.

The Security Bureau deemed her a security risk and arrested her.

"That is unfortunate," the man said, imagining the hissy fit the Mayor must have had when he heard the news. But the girl's flightiness inconvenienced himself as well, perhaps even more than it did the Mayor, since the execution of their grand plan was his part.

The strategy was to release their manufactured Elyurias strain—so named after the god their first test subjects worshipped, because the man had liked the sound of it—into the other quarantine zones in the next few weeks. The virus was to be introduced through a two-pronged method: One, through the exchange students they'd sent to the other zones, who would be injected at their next medical check-up in a week, and two, through physicians that the Mayor had planted in zones 1-5 months ago. The physicians would spread the virus randomly to the regular populace of the zones at their medical establishments, so as to throw off suspicion about the No. 6 students being the source.

The girl returning to No. 6 and refusing to return to her exchange in No. 5 was not a complete wrench in the works—everything would go off just as well with one less person—but it was a deviation from the man's plan, and he hated when his plans went awry even a centimeter.

He couldn't help but feel personally offended.

The man sighed again and employed his pale, spidery fingers in unrolling his lab coat sleeves as he calmed his wounded ego. He had been working with virus samples earlier, and it always felt like his sleeves got in the way of his thinking.

"I suppose the Mayor wants me to handle this?" he asked.

The Security Bureau officers gave a perfunctory nod, in perfect unison. They really were spectacularly trained, but then they had to be to do the unsavory things their government asked of them. The man had a notion of the intense screening and conditioning the officers went through before they were allowed to enter active duty, but their training had nothing to do with his research, and therefore he remembered none of the particulars. All he needed in an officer was the ability to keep mum and secure his test subjects.

"Right," the man said, inspecting his sleeves and deeming them in good order. "Her background, then? Will anyone come looking for her?"

"Unlikely, sir," said one of the officers, the older one who had a pleasant albeit impassive face. "Her late grandmother was her last of kin. The woman she visited the night we apprehended her is an old family friend, though they didn't seem to keep close contact in the last four years. The woman, however, is the mother of our last escaped subject. She hasn't shown any indication of unrest in reaction to her son's disappearance, so we believe she will not do anything in response to the girl's disappearance either. But we'll continue to watch her for signs of rebellion."

"Here is a file on the girl's particulars, sir," said the second officer and stepped forward to place a cream file folder on his desk.

The man didn't like this officer as much as his partner. His face was disproportionate, his nose taking up too much space, and he was quite a bit shorter than his fellow—all of which irked the man's OCD.

The man glanced over the girl's aptitude and health scores. "Smart girl. Pity."

He already knew that intelligence had no bearing on the results of virus trials, so it was a shame when he discovered a subject was more than usually intelligent. Such a waste of resources that could be put to better use in the advancement of the zone. But the girl had made a stupid decision in trying to rebel, and now it was his job to make sure she was put to as good use as her fallen state would allow.

He flipped the folder shut. "Thank you. You can tell the Mayor I'll take care of this matter. There's one experiment that's been kicking around my brain a while now. If we could get the virus to propagate in response to resonance…" He was quiet for a moment as he considered the variables involved. "Anyway," he said once he came back to himself, "the Mayor needn't worry himself over the girl anymore. You may go."

The officers bowed crisply and left the room to the man and his sinister calculations.

"Does anyone here ever talk about where the virus originated?"

Nezumi froze mid-yawn and lulled his head in Shion's direction.

It was just past lunchtime and they had settled into companionable silence, reading and relaxing, Shion curled with knees up in the faded chair and Nezumi reclined on the bed.

Shion had been reading a medical journal when the question bubbled to his lips, and as he watched Nezumi and waited for his answer, he absently pricked his finger on the corner of the journal's cover over and over because he liked the sensation.

Silently, he was measuring the probabilities of Nezumi's response being wary vs. detached vs. irritated. He looked tired with his head leaned back against the wall and a book flipped pages down on his lap, but his grey eyes were keen.

"No," Nezumi said. "Why would they?"

"I was wondering if people here might know—or at least talk more about it—since they aren't subject to the same restrictions as those in No. 6. You knew there was a vaccine created, so I thought the origin might be common knowledge as well."

"The vaccine isn't common knowledge. If it were, West Block citizens might seriously consider storming the walls of our good neighbor Quarantine Zone No. 6."

"...So why don't you tell them?" An angry mob outside No. 6's walls sounded like it'd be right down Nezumi's alley.

"Because," Nezumi drawled, as though he were talking to a slow-witted child, "it wouldn't work. They'd be mowed down as soon as they came within the wall patrol's scopes, and with that many bodies clogging up the streets, we'd have a mob of zombies on our asses. The only people who win in that scenario are the government officials, and I won't give them the satisfaction."

Shion nodded slowly. "That's a good point… We'd have to figure out a way to control the panic and reassure the citizens."

"What are you talking about?"

"If I'm able to turn my blood into a serum, we'd need to make sure we have protocol in place to deal with citizen panic, to let them know that as long as they're patient, everyone will be able to receive the vaccination."

"This again," Nezumi scoffed. "Shion, you're not making a serum out of your blood."

"Why not? I survived the infection. Something was different about me; I could be immune, and if I am, then I could inoculate everyone against it. I should. I have a responsibility to do so."

"You have no such thing."

The air in the room seemed to thicken and bear down on them. Nezumi set his book aside and slid to the edge of the bed. All traces of weariness had disappeared from his face; his eyes were dark and electric.

Shion's body tensed instinctively, but he forced his shoulders to relax, and said, "I do. Whatever Yamase had, it was different from the first wave. They may have a cure for the West Block strain, but there's no vaccine for the one I contracted. We have no way of knowing if or when it will spread, and if there's an outbreak in No. 6, I might be the only chance they have at stopping it."

Shion's mouth dried at the realization. What if there was already an outbreak in No. 6? They would never know until it was too late. He needed to find out if there was a way to check on the status of the city.

"I need to start on a serum, and soon. My mom lives there, Nezumi."

"So let me get this straight: Your plan is to manufacture a vaccine to the fancy No. 6 strain, hand it over to the government, no strings attached, and save all the poor ailing elites. All the while, everyone in West Block is slowly being picked off by the old strain, for which No. 6 already has a vaccine but refuses to share it. Does that seem right to you?"

"Well… No. It doesn't." Shion closed his book and laid it in his lap. "I still don't understand why, if the No. 6 government has a vaccine, they don't share it with the people. We wouldn't need quarantine zones if people don't have to worry about infection."

"Most of the world isn't like you, Shion. They don't care about other people, they only care about themselves."

"Well, that's wrong," Shion huffed. "If you can make a cure, then you have a duty to share it. And that's why, if I can make a serum, I'm going to do it. And I'll do everything in my power to get the vaccine to the old strain released. The government might want to keep it a secret, but I guarantee if you told the people of No. 6 about it, they would want the vaccine circulated."

Nezumi's hands fisted in the covers. "I bet you're wrong. I bet they'd horde it to themselves and keep the doors locked up tight against the world outside, just as they've always done."

"Agree to disagree."

Nezumi leered at him for a full breath. Then his hands relaxed their grip on the blankets and he shrugged a shoulder. "Fine. It's a pipedream, anyway. It's not like you can actually make a serum of your blood." He slid off the bed and flicked the kerosene heater on. "You can be as smart and hopeful as you want, but that's not going to make beakers and syringes appear. West Block doesn't have fancy medical equipment like that."

"I've thought about that, and I think I could convince Mr. Rikiga to get ahold of the equipment for me. You saw how much money and resources he has."

Nezumi stilled for a moment, but then straightened and raised an eyebrow at him, a sardonic half-smile playing on his lips. "That washed-up drunk? He won't help you unless there's something in it for him. Unless your serum can also cure alcoholism or get him laid, he's not going to want any part of it."

Shion scratched restlessly at the grooved fabric of his pants. "Maybe," he allowed. "But he and my mom were close, so he might be willing to help me out. I won't know until I ask." He took up his book and rose to place it back on the shelf on which he found it. "If I were able to explain the importance of the serum to him, how many lives it could save—"

Nezumi yanked Shion by the collar of his shirt and kicked the back of his knee out. Shion landed on the bed, hard enough to bounce once before Nezumi was on top of him, his knee pressed hard into Shion's arm and a hand pushing his opposite shoulder down into the mattress.

Shion scowled at him. "Ow?" He wriggled, but there was no escape. "Come on, Nezumi, you're being immature."

Nezumi's eyes glittered like ice shards. Out of the corner of his eye, Shion saw Nezumi's knife flash under the lights. He tilted his head up as the cold, smooth metal slithered against the underside of his chin.

The memory of the night they first met flitted through Shion's mind. Nezumi had pinned him to his bed just as quickly and easily then, and purred threats into his ear as he pressed a spoon to his throat. Shion had always remembered the moment with wonder and fondness, but seeing it reenacted now with a knife, he didn't feel quite so enamored.

"If I remember correctly," Nezumi murmured, "you said you'd punch me next time I put a knife to you." His voice was soft, affectionate. A cat taunting the mouse it kept captive beneath its paw. "So? Care to try?"

"No."

Nezumi's gaze had dropped to watch the trail of the knife against Shion's skin, but now the knife paused and Nezumi's eyes lifted to meet his. His mouth curved into a hungry, pitiless smile. "Because you know you can't."

"No," Shion said grimly. "Because you're being a jerk and I don't feel like kissing you."

"Tch."

The knife withdrew.

"I won't let you make a serum, Shion. If you try to, I'll destroy it. I hope you're right and a mutation of the virus is due to run rampant through No. 6. I hope it kills them all. They deserve it."

The pressure on Shion's arm and shoulder eased, and Nezumi drew back. Shion sat up and caught Nezumi's wrist.

"Why do you hate No. 6 so much?"

A muscle slid in Nezumi's jaw. "The whole zone is a eugenics project. One day a group of dusty old men decided half of the population deserved to live and the other half got to stay out here and be fodder for the undead. The people there couldn't give less of a shit whether we live or die. The whole place is built on blood and greed, and it deserves to burn."

Nezumi tugged his wrist, but Shion held on tightly, drawing it closer to his chest for greater control.

"No, I want to know your personal reason. Ever since I came here, you've told me to only care about myself, and forget everyone else. So you wouldn't expend your energy on hating No. 6 for anything less than a personal vendetta. So why? Is it revenge?"

Nezumi didn't say anything, and Shion's grip on his wrist slackened.

"For what? Did No. 6 do something to you?"

"That's not your business."

"It could be, if you told me."

Nezumi blinked at him. A slight smile crept into the corners of his lips—a real smile, not one laced with anger or cynicism. Though there was something sad about it.

"That so?" Nezumi said quietly. "You're saying that if I tell you, you'd be on my side one-hundred percent? You'd forget about making a serum and stand with me and watch as the dead consume the city?"

"...No." Shion's chest tingled with regret. "I couldn't do that, Nezumi. There are innocent people in No. 6. I won't abandon them."

Nezumi snatched his hand back and stood. The cold fury on his face was fierce enough to make Shion feel small and ashamed despite his resolve.

"You're always like this," Nezumi seethed. "You poke and prod and annoy the hell out of me asking, and then you can't handle what I tell you. I hate that about you. If you don't want the truth, then don't ask."

Shion bit his lip and turned aside. He didn't mean to. He didn't want to reject Nezumi's truths, but why did they have to be so harsh and unforgiving?

"Let's make this simple." Nezumi took Shion by the chin and made him look him in the eye. "Me or No. 6, Shion? You have to choose one, because you can't have both."

Shion wanted to shy away from the question, but he knew he had to answer this one. He always felt like this ultimatum was coming. Nezumi's hatred for No. 6 was inflexible, and so was Shion's belief in salvation.

He didn't want to go back to No. 6. He had no particular attachment to the place. Shion felt far more at home here in West Block, cloistered in the underground room, or laughing under the sun washing dogs while Inukashi cursed and grumbled at him.

But his mother lived in No. 6, and Safu. And though the government ruled through fearmongering and deception, the city was rife with beauty and beautiful people. He had created many fond memories there. He couldn't bear to see it all ravaged and destroyed.

But that was all Nezumi wanted: To see No. 6 brought low like West Block. Its people holed up in their houses, too suspicious to approach or trust or love those around them, for fear that they would turn and attack the next day.

Shion did not want to live in a world with that much darkness.

"I can see the answer on your face."

Nezumi's fingers were ice cold, but when they slipped off his chin, Shion missed their touch.

"You're always going to love No. 6 and I'll never stop hating it. That's why we're bound to become enemies. Someday soon, we'll have to go our separate ways." Nezumi's voice was quiet and faraway, as if already he was cutting ties with their relationship.

Shion's chest tightened. He didn't want Nezumi to be farther from him than he already was. He could take being held at arm's-length, but no more.

Nezumi glanced at the clock on the wall. "Shit. It's late; I have work."

Shion's breaths shallowed as he watched Nezumi snatch his boots from beneath the bed and tug them on over his thick, worn socks. A moment ago, they'd be in the heat of an argument, but all traces of annoyance and consideration had vanished from Nezumi's face, replaced by a placid purpose.

That's how quickly Shion was forgotten.

That's how quickly he would be forgotten.

One day, someday soon by Nezumi's account, Nezumi would abandon him. He would take his darkness and his storms and unleash them elsewhere, without a thought as to the damage it inflicted on those he'd left behind.

Shion grasped Nezumi's elbow as he tried to brush by. "I'm not your enemy. I never will be."

He squeezed tight as he said the words, and felt mollified when the corners of Nezumi's eyes pinched in discomfort.

"Don't underestimate me. You hate that I don't just accept everything you say? Well, I hate how you always look down on me. You always talk about the world like it's black and white, but it isn't. Things aren't that clear cut."

Nezumi lifted his chin and scowled down at him. "You don't know when to quit, do you?"

Nezumi took a step closer. They were nearly nose-to-nose, but Shion refused to be cowed; he did not step back and his glower didn't waver.

"If you think you can continue through life without sacrificing anything, you're lying to yourself," Nezumi said. "Eventually you're going to have to make a choice. You can't keep running away."

"Maybe there are some things I have to sacrifice, but not everything has to be either-or. Why can't I have both sometimes? Why can't I save No. 6 and keep you in my life?"

Nezumi scoffed, but Shion raised his voice and continued before he could voice any disparaging remarks.

"I refuse to be your enemy, and Idon't want to leave you. I'm willing to work with you and figure out another way, but you refuse to accept anything but your own views. I'm not the one who pushes everyone and everything away; that's you. You're the one who's running."

Nezumi bristled. Usually when he was angry, it was the cool, venomous sort, but now he looked as though he could spit fire.

Shion felt a sick thrill of accomplishment at the sight.

That's right. You're not perfect and you don't know everything, least of all about me.

They both opened their mouths to unleash their next assault—and the door bucked.

Nezumi and Shion jumped and whirled toward the sound.

"More of your friends?" Nezumi said, his voice low and wary.

"I don't think—"

Woof! The door rattled again, accompanied by the shred of dog claws down the rusty metal.

Shion blinked. Nezumi raised an eyebrow at him and he smiled sheepishly.

"Maybe," Shion admitted, and crossed the room to open the door.

Inukashi's little brother bounded in, looking excited and self-important. He barked at Nezumi, as if to say, "Nice to see you again," then sat at Shion's feet and lifted his head to show the note tucked into his collar. Shion laughed at this proud display.

Nezumi only clicked his tongue. "Inukashi poached my animal messaging system."

Shion plucked the note out and smiled. "They want me to work for them full-time as a dog washer! And they'll pay me!"

"Joy," Nezumi intoned. "You do that."

"I will," Shion said with a little of his prior snappishness.

Nezumi's eyes narrowed, but then he huffed. "Well, go on then. Doesn't the mutt want you to come with him now? I'll walk partway with you, since it's on the way and I'm already unforgivably late for work."

The dog nipped at Shion's heels as he hurried to get his coat.