Chapter 1

To see you one more time

“The name of the one who’ll wake you up someday is—Nagisa. Nagisa Natsunagi.”

That was the last thing Siesta said, and then the screen went dark.

After the film ended, none of us—me, Natsunagi, Saikawa, or Charlie—could speak right away. Silent moments ticked past, and my mind buzzed with the memories of what I’d just seen, the three years I’d spent traveling with Siesta.

We’d met on a hijacked airplane at ten thousand meters. Then, after an incident at my middle school, I’d set off on a journey with her. Our lives had been one long, dazzling adventure—and finally, our fight with the secret organization SPES had brought us to London, where we’d met a mysterious orphan named Alicia. She’d joined us as a proxy detective. However, Alicia had another personality, although she didn’t know it herself. That shadow personality’s name was Hel, and she was taking innocent lives on the streets of London.

To save Alicia, we headed for the enemy’s hideout in pursuit of Hel. There we encountered the enemy leader, who told us what the group really was. Then Siesta plunged into her final battle with Hel.

Yes, I’d finally remembered everything.

What had happened on that island a year ago.

Why the detective was already dead.

The one who’d taken Siesta’s life that day was—

“It’s me.”

Natsunagi murmured into the stillness. “Siesta… I’m the one who…”

“No.” I couldn’t let her finish. Reflexively, I cut her off. “You didn’t do anything, Natsunagi. Not personally. So…”

That was something I’d told Alicia—no, Natsunagi, when she’d used Cerberus’s seed to make herself look like Alicia. It was true, though: Natsunagi hadn’t done anything. Even if she’d physically committed a crime, the criminal was her other personality, Hel. Natsunagi had nothing to do with the heart-hunting incidents, or with killing Siesta. She hadn’t done a—

“I’m sorry.”

The lights in the room came up, and for some reason, Natsunagi turned to me and apologized. Her eyes were wet with tears.

“I’m sorry I took someone so precious away from you, Kimizuka.”

Her fingers approached my face. I thought she might shove them into my mouth, the way she’d done that one time, but instead her slim fingertips wiped my eyes.

“…Sorry.”

I was the one who’d been crying.

I thought I’d gotten over most of this stuff, but apparently not. I had to admit it: I still hadn’t managed to shake my lingering attachment to Siesta.

“So my memories were artificial,” Natsunagi said softly, looking down. “Even my ‘heart transplant’: I only stole Siesta’s heart. I bet those childhood memories of always being in the hospital were residual memories of my time as SPES’s prisoner. —As a person, I was always empty.”

Natsunagi had said those things frequently: She was a fake. She couldn’t become anyone. She couldn’t escape her small birdcage and fly away.

I’d heard Alicia put herself down that way, too. She’d talked about her amnesia like a dark room without light or sound.

Now that I’d retrieved that year-old memory, when I looked at Natsunagi, her image and Alicia’s blurred together. The Alicia I’d met in London last year had gone on to become Nagisa Natsunagi.

“Nagisa, come here and sit for a little while.”

Natsunagi’s shoulders were trembling. Saikawa called to her softly, and they sat down on the concrete floor together. As the older one, letting her do the comforting wasn’t my finest moment, but right now, I was grateful.

“You mean your memories were tampered with?” Charlie spoke up next. “Nagisa’s…and yours, Kimizuka.” She glanced at me. “In Nagisa’s case, we should probably assume they did it to soften the shock to her mind.”

I suspected Fuubi Kase, the redheaded detective, had been the one responsible. She must have done it on Siesta’s orders, to save Natsunagi.

“And I forgot.”

The fact that I’d met Natsunagi before.

The reason Siesta was dead.

What “SPES” actually meant, and the identity of Seed, their leader.

That pollen had taken my memories of those few hours on that island.

“But you remembered, didn’t you, Charlie?”

Charlie and I had come face-to-face with Seed last year at the enemy’s hideout. He’d introduced himself as the parent of all pseudohumans and told us what SPES’s real objective was. He’d claimed to be a literal seed who’d flown to this planet from outer space; he’d said his survival instincts were driving him to subjugate humanity. Then I’d gone to Siesta, but Charlie had stayed back at the lab and kept the enemy pinned down. That meant she hadn’t gotten hit with the pollen, which meant she’d kept her memories.

“Yes. I had no idea you didn’t remember, Kimizuka. After all, we weren’t comparing notes on every little thing… Especially since it’s, you know, us.” Charlie laughed at herself a little.

When Charlie and I met on that cruise, we hadn’t seen each other in a year. Then, on the deck of that luxury liner, we’d faced off against Chameleon, our sworn enemy. He’d told us he’d killed Siesta, but he was mistaken. Bet he’d never even suspected that Siesta had stopped her own heart.

“Charlie, I—” Natsunagi stood up suddenly, but…

“Don’t say anything.” Charlie didn’t even look at her. “I know it isn’t your fault. Really, I do. I just…haven’t completely come to terms yet. Wait a little while.”

“…Okay.”

That made sense; Charlie had only just learned how Siesta had really died. The girl standing next to her had had a hand in the death of the teacher she loved and respected. There was no simple platitude she could offer.

Just what sort of decision were we supposed to make in a situation like this? Once again, heavy silence filled the unfamiliar room.

“First of all…” After a brief pause, a girl’s clear, carrying voice spoke. “It’s all right, calm down. Your hands squeeze. Your shoulders roll. Your breathing is rhythmic. Close your eyes, take a deep breath, then exhale. Your blood circulates. When you open your eyes, your cloudy vision will be clear.”

The voice was Saikawa’s, and I’d heard her say those words before. It was her charm for relieving tension. “Once you’ve finished that, why don’t we have some tea?” The smile she gave us was as appealing as you’d expect an idol singer’s smile to be.

“Geez. Seriously, why are you the most mature one here?”

“Heh-heh! Because I’m far more experienced than you are, Kimizuka… Experienced.”

“Don’t try to suggest something with that. You’re an idol, Saikawa. Remember?”

I swear, this middle schooler… Well, that had probably been better than letting the mood stay heavy. With that thought, I turned to leave—and then, with a jolt, I remembered we were here because we’d been kidnapped.

“So where’s the kidnapper?”

I had a bad feeling about this, and I looked back.

“A tea party, hm? That sounds nice. Do let me join you.”

The next instant, I sensed someone besides the four of us.

“Who’s there?!”

On reflex, I reached for the figure…but the next thing I knew, I was flying through the air. I saw the ceiling, and then— “Ow!”

My back crashed into the ground. Something like an electric shock raced through me, and my eyes squeezed shut.

“Next time you attempt to touch this body, I’ll crush every bone in yours.”

Not fair. I slowly opened my eyes, planning to hit the culprit who’d thrown me with a few well-chosen words—then froze.

“You’re…”

The person in front of me was extremely familiar.

She had pale silver hair. Features as beautiful as a sculpture. And she was wearing…a maid uniform? Her taste in clothing wasn’t quite what I remembered, but her appearance was definitely right. For three years, I’d spent every moment with this girl, whose name was—

“—Siesta.”

There was no mistake. My former partner was standing right there.

Because you said to wear a maid uniform

“Please, go on. Order anything you like,” said the white-haired girl in the maid uniform. We were all seated around a table.

The five of us had relocated to a café for our tea party. It was roomy, but I didn’t see any other guests. Apparently, she’d reserved the whole place.

The person who’d brought us here said, “There’s no need to hold back on my account. Kimihiko’s paying.” She was elegantly sipping tea, a step ahead of the rest of us.

“Well, you’re welcome to hold back on my account, SIESTA,” I retorted at the girl who was sitting in the guest of honor’s seat.

With that dazzling white hair and those blue eyes, she was undeniably my former partner. But…

“You really do look just like Ma’am,” Charlie murmured as she watched SIESTA drink her tea, then nod approvingly.

This SIESTA wasn’t the real thing.

Of course she wasn’t. The detective had been dead for a year.

“Charlotte. As I told you, I’m merely a robot.”

She’d explained as much on our way here.

This SIESTA was a living android who had been created based on Siesta’s body, memories, and abilities.

“…You’re sure you’re not Siesta?” I asked. She looked completely human to me.

“Yes. Unlike Mistress Siesta, I don’t call you Kimi.”

“I see. Well, you’re right, the real one wouldn’t have pulled a shoulder-throw on me. She would have let me rest my head on her lap instead.”

“…I’ve run a database inquiry, and that never actually happened.”

“Hey, if you’re going to turn away, be more subtle about it. If you’re based on Siesta, you should be fonder of me.”

“I am contemptuous of you precisely because I am based on Mistress Siesta.”

“Okay, I want all my tears back.”

This was weird. The somber mood was vanishing like it never existed.

“What, did you rehearse this? You sound like an elderly married couple.”

“Yui, don’t compare them to a married couple. At least make it a veteran comedy duo.”

Saikawa and Charlie were sitting across from me. For some reason, they were both glaring at me. Gimme a break, this isn’t my fault. It’s all the detective’s fault… But this isn’t the time to be saying things like that.

“Since you kidnapped us, I assume you have some sort of business with us? Or did Siesta tell you to do this before she died?”

SIESTA was the one who’d kidnapped us and shown us that record of the past. The room where she’d locked us up was part of the hideout where she lived.

“Yes, Mistress Siesta made various preparations before that day arrived. Finding you was one of them; placing me here as backup was another. She instructed me to tell you the truth.”

“Would that normally take a kidnapping, though?”

“I had to. I couldn’t have told you otherwise.”

Then SIESTA turned her eyes to the one person who’d been silent all this time.

“Nagisa.”

That name was the last thing the detective had left behind.

Next to me, Nagisa looked up and heard the ace detective’s last words.

“Let me say this in Mistress Siesta’s stead: Thank you.”

The mood had been hazy all this time, but those words were like a wind that changed it once again. It felt as if SIESTA had appeared just to say this.

The rest of us took those words to heart right along with Natsunagi.

“Thanks to you, Mistress Siesta’s will has not vanished. In addition, preserving your life and sending you to school was her final wish—and her job. Consequently, you have my gratitude. Thank you.” SIESTA quietly bowed her head.

Natsunagi faltered. “I’m…” Her gaze swam and her lips formed soundless syllables.

We could say the “right” things all day, but there was no guarantee that they’d ease Natsunagi’s mind. Responsibility for the past seemed to weigh on her, and she looked down. Silence descended again.

“Why don’t we have our tea while we talk? This place has excellent apple pie,” SIESTA said quietly, and I realized that pie and black tea had appeared on our table.

“…That takes me back,” Natsunagi murmured, putting a small piece of pie crust in her mouth.

I noticed she was noting the memories, not the flavor.

“…Anyway, SIESTA.” I was speaking for all of us as I asked about the things we needed to know. “Why did you choose now to get us together and tell us about the past? Why hide the truth for so long?”

One year. That was how long it had been since Siesta died. If SIESTA’s mission had been to tell us the truth, why hadn’t she made contact sooner?

“There are several reasons.” SIESTA began to explain, holding up fingers as she did so. “First, it took Mistress Siesta a long time to suppress Hel’s vicious personality, which lies dormant in that body, and stabilize Nagisa.”

That was something Siesta had said during our last conversation—she’d mentioned that it might take a long time to seal Hel. Natsunagi herself had told me that she’d only recently been well enough to attend school. So it had taken a year to get all of that in place, huh?

“Second, I was waiting for the four of you to be on the same page emotionally.”

“Us?”

“Yes, because that was Mistress Siesta’s last wish.”

Right. That was the message from Siesta that Natsunagi had given me: Natsunagi, Saikawa, Charlie, and I were her legacy.

“But,” Charlie broke in, “why ‘the four of us’? Especially Kimizuka… Do we need him?”

“Hey, Charlie. Why are you acting like that’s a natural question to have?”

“It does seem as though she was torn about whether or not to include Kimihiko Kimizuka until the very end.”

“Why? I should be first! I was her assistant, remember?”

“Kimizuka, you’re not going to tell us the events of those three years were all a lie, are you? Are we about to learn you were just her stalker the whole time?” Saikawa asked.

“Saikawa, you have the best eyes here. What exactly did you see in those memories?”

It was hopeless. The second the mood eases a bit, these people launch into comedy routines.

“But…” As if she’d read my mind, Natsunagi gave SIESTA an earnest look. “You probably haven’t told us the most important reason yet, have you.”

Why had SIESTA assembled the four of us now? Why had she told us the truth? That’s what Natsunagi was asking.

SIESTA’s eyes narrowed, and she mentioned someone I’d forgotten about until just now.

It was the leader of SPES and, most likely, our greatest enemy.

“Over the past year, Seed hasn’t done anything of note. Recently, though, the situation seems to be changing.”

She was right. Saikawa’s sapphire incident and Chameleon’s attack on the ship were probably cases in point. What had he been trying to do during that year?

“Stopping him is your job, Nagisa.” SIESTA set her cup back in its saucer.

“My job…” The heavy role she’d been handed made Natsunagi lower her eyes. Usually, she would have thumped her chest, bursting with confidence, and accepted. However, now that she’d found out what was in her past…

“It’s not like she has to do this alone.” I gulped down the rest of my tea without coming up for air, then turned to SIESTA. “Saikawa, Charlie, and I all agree that we have to take down SPES. Natsunagi shouldn’t have to feel any more responsible for it.”

Natsunagi might have voluntarily inherited the ace detective’s will, but Saikawa, Charlie, and I were also part of Siesta’s legacy. Defeating SPES was a goal we all had in common.

“Yes, that’s true. However, Nagisa’s role in this doesn’t compare to yours, Yui’s, or Charlotte’s. After all…” SIESTA drew a little breath. “Nagisa is the ace detective.” As she spoke, she was clearly emphasizing the term.

“What about it? If you mean it’s a little different from being a regular detective, Natsunagi gets that already.”

Siesta had also called herself the ace detective, but she’d had very little in common with the normal concept of detective. Generally in a mystery, you’re not going to run into a detective who fights pseudohumans and aliens. Considering everything that had happened so far, Natsunagi had to be well aware of that already.

“…I see. So Mistress Siesta didn’t even tell you that.” SIESTA gave a pensive little nod. “The ace detective isn’t what you think it is, Kimihiko.” She spoke as if she’d read my mind. “You’re correct that it isn’t someone who merely solves crimes in the ordinary way. However, when we use the term ‘the ace detective,’ it generally means something different—”

“Wait.”

Just then, the table jolted noisily and Charlie stood up, spilling our tea. “If you say any more, you’ll be in violation of the Federal Charter.” She leveled an accusing glare at SIESTA. I had no idea what this Federal Charter was.

“It doesn’t matter. They’re already involved.” SIESTA looked around the table at us, then went on, her face still expressionless.

“The ace detective is a position. It’s one of the twelve shields that protect the world—the Tuners.”

The enemies of the world and the twelve shields

“The Tuners… So that’s what this is about…”

“Huh? You knew about this, too, Kimizuka?” Saikawa asked; she’d noticed my grave expression. “What on earth are the Tuners?”

“No idea.”

“Don’t act as if you know anything ever again.” The young idol was suddenly very cold.

“This world is under near constant threat.”

Ignoring the witty repartee Saikawa and I had going, SIESTA went on with her explanation.

“These crises strike regularly, and sometimes several happen at once. In an effort to combat them, an international organization has secretly appointed individuals known as ‘Tuners.’ ”

Someone created to face the world’s crises… Now that she mentioned it, I got the feeling Siesta had said something like that once. Something about how she existed to protect the world. About having that sort of DNA.

“There are twelve Tuners scattered across the globe. They are assigned various missions to handle global crises, and each occupies a different position.” As she counted, she folded her fingers down, one by one. “Phantom Thief, for example. Oracle. Assassin. I’m told there’s even a Magician and a Vampire.”

“ ‘Vampire’…?” What kind of job is that? I can’t imagine what sort of work they’d do.

“Since they serve as a bulwark against threats to the world, many historical perils have been averted.” SIESTA went on, explaining clearly. “Nuclear war, climate change, pandemics, impact events. In some cases, humanity itself has been the source of the threat. In others, as with SPES, threats have come to this world from elsewhere. Either way, the Tuners have always fought these crises from the shadows.”

“Then without them, the world would have been destroyed and we just never knew?”

“That’s right. It’s even said that one of the twelve held back the King of Terror who should have attacked in 1999.” SIESTA listed a major prophecy by Nostradamus that had once rocked the world to its foundations, as if it was just one possibility among many. “The world line on which we’re living now may actually be a future that was rewritten by the Tuners.”

“Don’t tell me… Are you saying it’s actually possible to change history?”

“Declaring that what can’t be observed doesn’t exist is the height of arrogance. Besides, you know of one such case personally, don’t you, Kimihiko?”

I searched my memory for something applicable and came up with… “—The sacred text.”

It was the book Hel had told me about a year ago, the one that held a record of the future. Could its author have been someone who actually knew the future?

…No, I couldn’t afford to take things that far off topic right now. More importantly, now that I knew about the Tuners, I could put together one thing from what SIESTA had said so far with near certainty.

“So Siesta was a Tuner, then.”

SIESTA affirmed my guess wordlessly, by taking a sip of tea.

Siesta had been one of the twelve Tuners who saved the world—and her position had been ace detective. Her mission had been to bring SPES to heel.

She’d never said a word about it. However …

“……”

Charlie was biting her lip, and one look at her profile told me it was true. Siesta had talked about fighting the enemies of the world almost as if it was a mission she’d been given, but there had been something much larger behind it.

“That said…” While I was still thinking, SIESTA went on. “Last year, when Mistress Siesta died, the seat of ace detective became vacant. Since then, no one has been in charge of subjugating SPES.”

“What are the other Tuners doing? They could take over for her.”

“It’s not like SPES is the only global crisis,” Charlie said. “The other eleven Tuners have jobs of their own to do.”

“I see. So SPES isn’t the world’s only enemy…”

Then even as we spoke, some other threat was heading for the planet…and someone else was fighting it?

“Returning to the subject at hand…,” SIESTA said, looking at Natsunagi. “If nothing changes, it’s likely that you will be named as the next ace detective.”

“…! I…will?”

Natsunagi hadn’t been expecting that, and her eyes widened.

“Nothing’s settled yet, of course. However, you do have the former ace detective’s heart, and you’ve taken up her will. You can also take full advantage of powers ordinary humans don’t have. Many will feel you have what it takes to fill the position.”

I see. So Natsunagi hadn’t just inherited Siesta’s heart and her will. They thought she had the capacity to make the most of her power as well. But…

“Siesta won’t speak through Natsunagi anymore.”

During that battle with Chameleon on the ship, Siesta had borrowed Natsunagi’s body to appear to me—and then she’d vanished. It hadn’t been a miracle or a deus ex machina development. She’d loved teasing me, and she’d shown me a transient daydream.

“Yes, I’m aware of that. And so”—SIESTA turned back to Natsunagi—“in Mistress Siesta’s place, let me ask you, one more time: Nagisa, do you really intend to inherit the ace detective’s will?” She was testing Natsunagi’s resolve.

“I…” Natsunagi’s voice was trembling.

“What if…,” I cut in. I didn’t have a plan or anything. It just seemed too mean to ask Natsunagi to make a decision like this right now. “Let’s say that, someday, Natsunagi takes over as ace detective. What would she have to do first?”

It didn’t have to be right now. I was simply asking about a hypothetical future.

“Let’s see…,” SIESTA said. She sipped what was left of the tea in her cup, and her eyes scanned the four of us.

“In that case, I would like you to find the mistake that was hidden in the past I showed you.”

Occupation: student, occasional assistant

The day after that, I was at school, sitting in class.

I’d completely forgotten that summer break classes were a thing.

This may seem like it’s coming out of nowhere, but I’m a regular student before I’m a detective’s assistant, at least as far as society is concerned. The other day, I’d sauntered off on a cruise and gotten kidnapped et cetera on what was supposed to be my break, but…apparently students in their last year of high school don’t even truly get respite during summer vacation.

“It’s still only been fifteen minutes?” A glance at the clock on the wall plunged me into despair. This class had begun in the morning as a “summer extracurricular,” and it had been dragging so slowly that I suspected it might last forever. There was still more than half an hour left before lunch.

“Guess I’ll just sleep.”

Sleeping is a student’s duty. I’ve heard that sleeping children grow well. Perfect, I was just thinking I’d like to be three centimeters taller. Come to think of it, Siesta slept a lot too. Is that why she grew so well in all those intriguing places?

“…Huh?”

Yikes, was that a shitty thing to think?

I was tired. That had to be it. After all, way too much had happened yesterday.

My seat was at the very back of the room, on the hall side. I slumped over my desk, shut my eyes, and got the inside of my head in order.

Yesterday, SIESTA had told us that the world was protected by twelve Tuners, and that Natsunagi was about to be appointed to one of those positions: ace detective.

If Natsunagi took that role, the first thing SIESTA said she’d have to do was find the mistake. Then she’d filled us in on the details. According to her, there had been a certain error in the footage we’d been shown from last year. If Natsunagi wasn’t sure whether to become the ace detective, she could work on finding that mistake first, and decide later. That was the last thing she’d said before she released us.

In other words, what I—or Natsunagi—needed to do now was find some sort of error hidden in the revelations about last year.

“We don’t have any clues, though,” I muttered, quietly enough that nobody would hear.

…The next thing I knew, the room had gotten kind of noisy. Class had ended while I wasn’t paying attention, and it was finally lunch. I just had to get through two more periods in the afternoon, and then today’s extracurriculars would be over. Figuring I’d go grab a convenience store bento the way I always did, I raised my head, and that’s when it happened.

“Oh.”

I made eye contact with a girl in the corridor—Nagisa Natsunagi. She was probably headed to the cafeteria with some friends; she was with three or four other girls who all looked sort of trendy.

Perfect timing. We needed to discuss our plan of action. I stood up, meaning to set up a time to meet after school, but—

“……”

She averted her eyes, avoiding me.

Her friends giggled, whispering something to her. Natsunagi waved her hands and shook her head in emphatic denial, and they all walked off.

Is this hell? Felt like every eye in the classroom was on me. I dropped into my chair again and went back to sleep.

“How long are you planning to nap?!”

After class, a joking voice woke me up.

My eyes were blurry with sleep. I rubbed them, and a hazy figure came into focus. “Hey, I just resolved two incidents. I was finally settling down.”

I hadn’t been sleeping all that time. True to my status as a trouble magnet, I’d just finished clearing up some minor issues my classmates had brought to me after school.

“And actually, I’m not talking to you anymore, Natsunagi.” I glared at her, remembering the way she’d treated me earlier.

She was sitting sideways at the desk in front of mine, turned to face me. “Look, I’m sorry. Geez, you’ve got bedhead.” Natsunagi marched right into my personal space, combing my hair with her fingers.

“What are you, Siesta?”

“Only half.” In the dim orange light that lanced through the windows, she gave a faint smile.

The sun was almost down, and the two of us were the only ones left in the classroom.

“And? What do you want, Natsunagi?” I smacked her hand away from my head.

“What do you mean, ‘what’? You sent me a signal at lunch, remember?”

“And who was it that ignored it and went off somewhere?”

Nothing hurts worse than knowing the girls at your school are whispering about you, all right?

“…Well, they teased me.” Natsunagi gave me a reproachful look. “They were, you know, asking if you and I were ‘together like that.’ ”

“Don’t get embarrassed about that kind of gossip.”

“I didn’t mean it that way.” Natsunagi puffed out her cheeks and tugged on my bangs, as if she was trying to communicate something. Seriously, what?

“Listen, you sleep too much. Just how many hours do you think I waited?”

“Bold words from somebody with red marks on her face.”

“Hey, why didn’t you tell me sooner?!”

“And you should wipe off your drool.”

“I’ll double-kill you!”

Natsunagi pushed my head down onto my desk. Not fair…

“…So? What did you need?” she asked again, after she’d finished wiping her face. Her eyes were on the setting sun outside the window. It was almost down.

“…Right.”

I started to bring up what I’d been planning to talk about… But, for some reason, the words wouldn’t come.

It wasn’t just me. Natsunagi had to know what I wanted to talk about. When it came down to it, though, neither of us could broach that subject.

“So you’ve got friends, huh?” I made random small talk instead.

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