Interlude
AFTER SHIORI became a crosswalk ghost, the field of imaginary science progressed at an astounding rate. One of its global achievements was the IP band the director had been focused on—a wristband device that could display, in numbers, what world the wearer was currently in by measuring its Imaginary Elements Print. Once the prototype was complete, tests were performed at laboratories all over the world, and a few years later, even ordinary citizens were enlisted to test them out.
The ISRI’s research had taken a big step forward as well in terms of my dad’s main focus: IP stabilization. This research involved observing imaginary elements overlaid in an imaginary space, then freezing the quantum state and preventing any flux. Were we to achieve this, we would then be able to prevent parallel shifts, or so the theory went. If this technology could be made widely available, we’d be able to prevent all sorts of accidents, such as those caused by shifting while driving, among others. Humankind needed this technology if we were going to embrace parallel worlds as a part of our everyday lives. That said, we still hadn’t found a way to directly observe imaginary elements, which remained the key to our research.
Last but not least, progress had also been made on the Cradle of Einzwach, the device used for parallel shifting at will. All the data they gathered from my trips must have contributed a lot. But of course, because it counted as human experimentation (and on a minor, no less), the only people who knew about it were me, Dad, and the director.
She christened this new, voluntary type of shifting as “optional shifting” and made it the lab’s main goal to find a practical application for it within the next twenty years. If we could finalize this tech, we could possibly share information between parallel worlds concurrently, and at that point, not just imaginary science, but all fields of civilization were predicted to make great progress.
In contrast with the stellar outlook for imaginary science, however, my personal life quickly soured. After Shiori’s body was taken from the world, the only emotional support I had left was her ghost.
Originally, I was planning to graduate high school and enroll at Kyushu University Faculty of Science, Department of Imaginary Science. It was at Kyushu U’s physics department that our director first started independently researching imaginary science. From there, she transferred to a graduate school in Germany, and finally came back to Japan and became the country’s youngest professor. With financial backing from her hometown, she then established the Imaginary Science Research Institute, of which my father was a co-founder, and the rest is history.
Back when I was ten years old, she first announced she had proven the existence of parallel worlds at a scientific conference. In a blink, imaginary science became its own field of study, and “that weird laboratory in Nowhere City” became a household name around the world. In response, Kyushu University added a Department of Imaginary Science to its Faculty of Science. A handful of researchers, including the director, were invited to teach there part-time, and Kyushu U quickly became the number one school for imaginary science—not just in Japan, but in the world.
In the beginning, my plan was to study imaginary science there, then come home and research how to save Shiori. But when her body died, it was all over for me. Attending that school would’ve required me to move to Fukuoka, leaving her ghost at the intersection all alone. I couldn’t abandon her. It would be too cruel.
Instead, I dropped out of high school and got a job at the lab. I wasn’t even remotely qualified, of course; I was a total nepotism hire. But Dad and the director sympathized with me—perhaps a bit too much, honestly—and all the other researchers had known me since I was a kid. You could at least say I was a good cultural fit.
At eighteen, I started receiving a monthly salary as an official employee. After that, I moved out of Dad’s house and started living on my own. I could barely afford my living expenses, but I was fine scraping by. Then, I dug up the “remarriage” conversation that had gotten shelved after what happened to Shiori, and after a little nudging, Dad and the director got married the next year.
Granted, I didn’t do it because I wanted them to be happy. I mean, I did want that, obviously—but my biggest objective, more than anything, was to be alone. I wanted to think of nothing but Shiori, as much as possible; I wanted to devote all my free time to the intersection. That was why I needed my own place. Still, I had just enough humanity left in me to worry about my aging father being all on his own. Maybe they were so amenable to getting remarried because they could tell I felt that way too.
And so, with my newfound alone time, I visited the intersection every day to see Shiori. The only other thing I took seriously was my research. I hadn’t given up on saving her—I was still conducting optional shift experiments using the IP capsule (the official name for the pod the director previously called the Cradle of Einzwach), and I was starting to work my way toward long-distance shifts. But even after nearly a hundred experiments, every Shiori that had come into contact with me had succumbed to imaginary karyomitosis.
In more distant worlds, there were Shioris living happy lives that I had never been a part of, but I just couldn’t see those parallel Shioris as the same Shiori I loved. To me, there was only the one. And the more worlds I visited, the stronger this sentiment grew.
Around this time, I became obsessed with my “fate” theory, convinced that the act of meeting me had single-handedly ruined her life in every single world. After consulting my dad and the director, I started calling it the causality radius. If a given event happened in one world, it was all but guaranteed to happen in every world within a certain proximity. Conversely, the farther the world, the less likely it would happen. I wanted to quantify that radius.
Using the Sea of Einzwach model, the event in question would count as its own macro-bubble. Inside it, a micro-bubble with a specific outcome would split into parallel worlds, all trapped within the same causal set. Unable to escape, these worlds would all arrive at the same outcome, with no exceptions—or so my theory went.
With the lab’s help, my theory was proven, then promptly accepted as an official doctrine of imaginary science. Because the distance was measured by IP, the concept was formally named the Schwarzschild IP (SIP), referencing the term used to measure the radius of a black hole. (Incidentally, the director helped me name it, and I suspected she was once again inspired by some old piece of fiction.)
Once my theory was accepted, this young high school dropout started making a bit of a name for himself. But I had no interest in fame beyond the funding it helped me get for my research. I still had only one goal—to rescue my Shiori.
But oh, the irony. My SIP theory had just proven that there was no way to save her. Because, you see, my first encounter with Shiori was its own causal set. That meant that in every world therein, she had been turned into a ghost.
We still hadn’t established a method to directly observe imaginary elements, but even if we did and we could pinpoint precisely where her imaginary elements were stuck, we no longer had a physical form to attach them to. Her body had become ashes years ago. At this point, I could only think of one possible method with which to save her—and only one way to achieve it.
Parallel shifting, as the name would suggest, was a lateral transposal through imaginary space. But no amount of lateral movement would help me. If I wanted to get anywhere, I needed to move vertically.
In other words…time travel.