After I put Mom on babysitting duty and convinced Kazune to come with me to the lab, we found Dad and the director waiting for us.
Over the phone, Dad had told me our IPs were locked—mine and Kazune’s. Normally, the only time someone’s IP was locked without their consent was when they were involved in some sort of crime. The only crime I could think of was the incident on New Year’s, but the cops already had the guy—so if it wasn’t that, then what else could it be? When I asked Dad for details, however, he told me he’d explain everything in person.
Hence why the four of us were now sitting in this soundproof meeting room with the door locked and our phones in airplane mode.
“To put it simply, your parallel selves are prime suspects in a murder case.”
“…What?”
It struck me like a bolt of lightning, and Kazune’s eyes went as wide as saucers.
“The locks went into effect last night, and the cops delivered the paperwork this morning. They say the murder took place two nights ago with a relative SIP of 22, plus or minus 10. Granted, with a range like that, normally you wouldn’t be involved at all, but…”
SIP was short for Schwarzschild IP, which referred to the range within which a given event was ensured to take place inside each parallel world. An SIP of 22 ± 10 meant that, relative to our World Zero, the event had taken place across worlds 12 through 32, with World 22 at the center. And since 0 was outside that range, yes, one would think our world wasn’t involved. But my father wasn’t finished speaking…and I could guess what he was about to say.
“Record of an unauthorized optional shift was discovered within that very same SIP, traveling a distance of 13 worlds. And the shifter was you, wasn’t it, Kazune-kun?”
“…Yes.”
Indeed, this Kazune had an IP of 13, which just barely fell into that SIP range. It was hard to say she was entirely unrelated.
“We gathered all the information we could before you got here. The murder took place two nights ago, between the hours of 8 p.m. and 11 p.m. The scene of the crime varies from world to world. Take a look at this map.” He unfolded an old-fashioned paper map. Our home address was marked on it, as well as a handful of other numbered spots. “These are all the crime scenes across the entire SIP.”
I looked at each one in turn. Some were buildings, some were alleys, some were public parks. The only thing they seemed to have in common was their relative proximity to our house. But more importantly…
“Are you absolutely sure about this one?” I asked, pointing to one of the buildings marked on the map.
Dad grimaced, then nodded. “Yes, we triple-checked that one. It’s your house, all right.”
In a parallel world, my own house was the scene of a murder?
“You’re joking… Why…?”
“Well, when you see the victim, you might get your answer.”
Next, he laid out a profile sheet with a photograph of what I assumed was the murder victim: a woman in her forties. I didn’t recognize her face, and her name didn’t sound that familiar, either…at first.
“Wait… That surname…”
“Yep. The New Year’s stabber? This is his wife.”
One by one, the puzzle pieces were coming together…though I didn’t want them to.
“In our world there were no fatalities, but about 20 worlds away…I’m told Ryou was killed. Naturally, the story was about a thousand times more viral there, so your house was all over the news. That was how the killer’s wife learned your address. Then, two nights ago, she visited in person to apologize…”
And then she was murdered. Given the circumstances, it was no wonder Kazune and I were the prime suspects. In a range of parallel worlds not too far from here, my son Ryou was stabbed to death. Then, another murder happened across a smaller cluster within that same range, at my house, and the victim was the stabber’s wife. The number one suspect was obviously—
“I’m told the cops are looking at our Kazune-kun as their number one.”
“What?! Why her?!”
My prediction was wrong in the worst possible way. Surely the evidence pointed to me, not her! Nearly all the Kazunes currently within that SIP range had shifted there against their will from worlds where Ryou never died. In short, they had no motive. Plus, the Kazunes who caused the shifts—the ones who lost their sons—most likely only did so out of grief for Ryou. In a way, they were victims too!
“No, that can’t be right! My Kazune didn’t choose to shift there! What motive could she possibly have?! It’d make more sense if—!”
If the murderer had fled here. I choked the words back down right before I let them slip. That wasn’t something I had any business blurting out thoughtlessly.
“Settle down, Koyomi. There’s a reason they’re looking at her. Part of it’s because the murder happened after she shifted there, but more importantly, it’s because of her alibi.”
“What, so…she’s the only one who doesn’t have one?” I asked.
“On the contrary—in almost all cases, she’s the only one who does have one. But upon formal investigation, most of those have fallen through.”
What the hell? He made it sound like…like Kazune faked her alibi or something!
“In each of the parallel worlds, her alibi is predominantly based on your testimony. But cops don’t trust testimony from family, so they looked into it…and found proof of you forging evidence to substantiate it.”
“…I can’t believe it…”
So in summary…after Ryou was killed in a parallel world, a grieving Kazune fled here, to a world where he was still alive. In exchange, my Kazune was sent to the world without Ryou, learned of his murder…and a few nights later, upon receiving a visit from the killer’s wife…killed her? Then my parallel self tried to protect her with a fake alibi, but the cops saw through it, and now she’s the prime suspect?
“That… That’s ridiculous!” Before I knew it, I had slammed my fist on the table. “Kazune can’t possibly be the killer! She has no motive! She—!”
Still has her son. But I didn’t dare say those words in front of Kazune 13.
“The Gate of Einzwach.”
At first, I didn’t realize who had spoken…until…
“Director?” my father murmured. What did she just say? Einzwach?
“By passing through the gate, even the purest and most innocent will turn into cold-hearted killers. A novelist proposed its existence a few decades back.”
This whole time, she sat staring down at the table like this conversation bored her to tears. What did this “Gate of Einzwach” have to do with anything? Was she trying to say Kazune had passed through it? As if! Humans couldn’t change overnight!
The director glanced up, and her bottomless eyes bored into me.
“…Okay, well, unlock our IPs,” I shot back. “We need to get our Kazune back and talk to her.”
“Koyomi, you know we can’t do that without police authorization,” said Dad.
“Sure you can. You’re just not supposed to.”
“As director, I don’t think I can allow it,” the director chimed in. “Too much of a hassle all around.”
With the ISRI’s two highest authority figures opposed to it, it wasn’t going to happen. But what else was I supposed to do?
“For right now, go ahead and take some time off from work. We’ll let you know if we learn anything. Just stay calm and wait.”
Stay calm? How was I supposed to stay calm in a situation like this?
The most I was permitted was to make photocopies of the police records to take home with me, so that’s what I did…all the while wrestling with my love for Kazune 0 and Kazune 13.