Causality Constraint

Before I knew it, midnight had come around once more.

The instant the clock struck twelve, the blue status window burst into view before my eyes—yet today it seemed there had been no real harvest at all.

I even checked the revised diary entry for Sunday, but there was nothing ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠of note. Since we hadn’t met, my past self hadn’t been able to do much of ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠anything. Still, Monday was school again. Starting today, I would approach Ijin once more.

There was good news, too. Over the past three days I had gathered ten points, enough at last to buy the cheapest ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠item in the shop.

Without a moment’s hesitation I tapped the shop tab and purchased Past Observation Authority ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠Unlock — 10p.

The moment I touched the screen, static crackled across the status window and a vivid 4K video feed unfurled like a living screen. At last I could watch the past in real time instead of with a one-day delay.

The place reflected on the display was the shabby studio apartment I had lived in five years ago. Thank goodness I lived here now; back then I had no idea how I managed to survive.

“Ah……”

A soft exclamation slipped out of me as I looked around the room.

It was the space I had decorated with such eager excitement as a college freshman—familiar major textbooks, outdated appliances, and there on the bed, mouth hanging open in sleep, was my twenty-year-old self.

That painfully poor, scruffy landscape of youth stirred a strange nostalgia. I had been such a pathetic mess back then.

It was late, so there wasn’t much to see for now. Tomorrow morning I would wake up and watch what my past self got up to.

For three whole days I had been dying of curiosity about whether I was handling things well. Being forced to understand process and result through nothing but words in a diary was nothing short of torture. I went straight to sleep.

Birdsong and warm sunlight greeted me. The instant I woke I flung open the status window.

Morning of March 22nd. My past self was sitting in a lecture hall for a major class, baseball cap jammed carelessly on his head. He must have rushed in, afraid of being late.

While I was gazing at the familiar university classroom building, Ijin suddenly appeared, setting her bag on the seat beside me to claim it in advance. She spotted me, broke into a bright smile, and came over.

The two of them sat side by side as if it were the most natural thing in the world, sharing the little snacks she had brought and chatting. Watching from my corner of the room, the corner of my mouth curled upward of its own accord.

It felt genuinely heartwarming. In the original history I wouldn’t even have been able to meet her eyes, yet my past self had clearly stepped inside Ijin’s circle. Right now I was probably the person she was closest to.

But my peaceful satisfaction did not last long.

When the lecture ended, Ijin said goodbye and headed for the liberal arts building. I had a free period; she was off to University English.

That class was packed with English debates and group presentations—the terror of the semester that Ijin had hated with every fiber of her being.

My past self, after sending her off alone, was waiting quietly in front of the student union building so they could grab lunch together once her class finished.

I closed the status window for a moment and started boiling ramen. Watching a college romance drama had made me hungry.

After finishing the meal I opened the window again and saw my past self still waiting to meet Ijin after class.

And then—thud.

My heart plummeted into the basement. My eyes trembled; my hands slipped free of my will.

The heavy classroom door swung open and students poured out. Through the crowd strode Kang Minjun, tall and model-handsome in a perfectly fitted shirt. And right beside him was Ijin.

“……Ah…”

A groan tore from my throat.

Ijin kept glancing up at Kang Minjun and bursting into peals of laughter. As the top student of Chemical Engineering and an elite through and through, Minjun must have led their group with overwhelming fluency in that infamous English debate class. Ijin, whose English was only basic, had clearly been captivated by that perfect display.

All the anticipation my past self had felt while waiting turned meaningless; Ijin never even noticed me standing in the side corridor. She locked eyes affectionately with Minjun, let out soft little hums of praise, and walked off with him toward the restaurant street outside the school gates as if it were the most natural thing in the world.

Until their figures disappeared into the distance on their way to lunch together, my past self simply stood there, staring blankly after the two of them.

Watching the live feed from my studio apartment, my hands began to tremble finely. The ramen I had just eaten threatened to come back up.

A crushing sense of defeat, as if a massive lock had been clamped shut, surged over me like a tidal wave.

“So in the end…… nothing changes…”

I had twisted the past just enough to snatch the “close male friend” title, yet in front of that perfect alpha male named Kang Minjun it meant nothing. Ijin was instinctively drawn to him.

The original history felt like an absolute wall—an unstoppable current no amount of thrashing could overcome. Even if the future changed, it seemed I still couldn’t beat that bastard.

Just as I was about to hang my head in misery, the past me on the CCTV-like screen moved.

After losing Ijin to Kang Minjun and eating cafeteria food alone, my past self showed not the slightest sign of being cowed. The moment Ijin’s afternoon class ended and she came out alone, he stepped right into her path.

His face—carrying the memories of the future me—held a glint of pure venom in the eyes. He casually caught the wrist of the exhausted Ijin who had been through back-to-back classes.

“Hey, Han Ijin. Where’d you go for lunch? If you’ve got nothing after this, how about we grab dinner together?”

Caught off guard by the sudden invitation, Ijin flushed pink yet followed behind my past self without protest, looking far from displeased. The brief opening that appeared after lunch with Minjun—my past self had slipped into it with perfect precision.

Unlike the present me drowning in despair, past me was already setting up the next move.

The two of them headed for a quiet little barbecue place near campus.

Through the fragrant smoke of sizzling pork belly, Ijin rested her chin on her hand, looking far more at ease than usual. After a full day of classes and the tension of trying to look good in front of Minjun at lunch, she must have been exhausted.

“I was starving, so this is perfect. I really love meat, you know. If there’s no meat I barely eat at all.”

My past self casually tossed a lettuce wrap onto Ijin’s plate.

“Oooh~ You’ve got better sense than I thought.”

I couldn’t help murmuring in admiration at the sweet side my past self was showing.

“Is that so? I like meat too. But where’d you eat lunch?”

“Uh… um… I went to that pasta place with someone from the liberal arts class.”

Ijin pointed vaguely behind her. My past self thoroughly hid any trace of jealousy and kept the conversation going.

“Oh yeah? What’s that person like? I want pasta too~”

“We formed English debate groups today, and there’s this guy named Kang Minjun from Chemical Engineering. He’s seriously amazing. I thought he was a native speaker, no joke. I was totally zoning out and he carried the whole thing!”

Ijin’s eyes sparkled as she talked about Minjun, but then she let out a deep sigh.

“He’s nice and everything’s great, but it felt a little… suffocating. He’s so perfect that every time I open my mouth I feel like all my shortcomings are on full display.”

At that confession the corner of my past self’s mouth twitched upward. Sitting here all day doing nothing but staring at the screen, I smiled silently as well.

Judging by both past Ijin’s and present Ijin’s words, Kang Minjun was consistent as ever. Thinking about it again, that arrogant, perfection-obsessed personality was the complete opposite of Ijin’s.

The little scraps of information and emotional threads she let slip about Minjun were becoming excellent data for the present me.

“See? Isn’t hanging out with me—grilling pork belly and talking freely like we did at the MT—way better than being with a guy like that?”

My past self slid another piece of meat onto her plate and gave her a light, teasing poke.

“Tch… Well, yeah. Being with you is definitely more comfortable.”

Ijin laughed and lightly smacked my arm. In that small bit of skinship and the playful exchange of glances, a subtle, unfamiliar tension began to flow between them—a ticklish current of something more, as if they were ever so slightly stepping over the line of mere close friends into the realm of budding attraction.

After finishing dinner they walked along a small river. Every time the spring breeze blew, Ijin’s long hair fluttered, and even through the screen her profile under the streetlights was breathtakingly beautiful.

“Seonwoo.”

Ijin stopped walking and turned to look at me.

“Yeah?”

“It’s just… being with you like this feels so much more at ease than when I was with Minjun earlier.”

She ducked her head shyly and kicked at the ground with the tip of her shoe. I couldn’t see clearly, but both her cheeks were faintly flushed.

My past self, seeing her like that, seemed to make up his mind and was about to speak.

But the status window flared red and a warning blared.

I flinched hard. And my past self seemed to have seen something and flinched right along with me.

So he could see the status window too, huh.

The current of attraction flowing between them fizzled out without the decisive line my past self had been about to deliver. They parted without any further progress.

The moment my past self walked Ijin to her door and turned away, the clock at the top of the smartphone screen hit 00:00.

Ding-!

The numbers jumped up in a satisfying way. Timeline Alteration Rate up 0.5 percent, Favorability up 3 percent.

Even if the visible figures were still modest, I felt not the slightest impatience. I had seen the cunning, composed attitude my past self displayed on the screen.

The real source of unease, however, was the system itself—the thing that had blocked my more aggressive moves.

Even as I lay down to sleep, the unfairness kept me awake.

“I was about to take the next step, so why slap a restriction on me? Is the system basically telling me I can’t change the fact that Kang Minjun and Han Ijin end up together? Still… I’ll use every means and method I have.”

I ground my teeth at the ceiling, pouring out my rage, and at last my eyes began to close.