The sun had almost completely slipped beneath the western horizon, leaving behind a smear of bruised purple and deep indigo that hugged the silhouettes of Rajawali High School. The campus was eerily quiet. The "normal" students had long since returned to their homes, enjoying warm dinners or preparing for expensive tutoring sessions. The security guards had begun their routine patrols, the metallic clatter of closing gates echoing through the desolate courtyards.
However, on the third floor, within the laboratory affectionately dubbed "Rehan's Cave," digital life was just beginning.
Rehan sat in the same position he had occupied for hours. His hollowed eyes reflected the steady, hypnotic scroll of green and white code across his monitors. He had just finished Alya's "special order"—a sophisticated manipulation of the school's procurement database.
On paper, the physical delivery order for the pharmaceutical warehouse requested fifty million rupiahs' worth of antibiotics and IV sets. But digitally, the invoice sent to the School Treasurer was masked as "Premium Hand Sanitizers and N95 Masks" of the exact same value.
The school's official funds went out, and the "contraband" supplies were slated to come in. There was no price discrepancy, no financial imbalance to trigger an audit. It was a masterpiece of digital art—clean, surgical, and utterly untraceable.
Rehan stretched, his spine letting out a series of satisfying cracks. He thought his day was over. He thought he could finally retreat into his sacred sanctuary of solitude.
But then, the motion sensor in the corridor—an illegal installation linked to his third monitor—flashed a violent, rhythmic red.
Someone was outside.
Rehan clicked his tongue in annoyance. "Who is it now? Did Dani forget his controller again?"
He shifted his focus to the corridor's CCTV feed. On the grainy, monochrome screen, he saw a slender figure wearing an oversized jacket and a backpack that looked suspiciously heavy. The figure didn't bang on the door with Dani's characteristic brutality. He didn't look around in a panic like a lost student.
The figure simply stood before the glass door, staring directly into the hidden camera lens tucked into the corner of the ceiling.
It was Salim.
What made the hair on the back of Rehan's neck stand up was the expression on Salim's face: he was smiling. He knew Rehan was watching. Salim then held a scrap of paper up to the camera lens. Written on it was a string of binary code: 01001000 01000101 01001100 01010000.
Rehan frowned, translating the binary in his head within seconds.
H-E-L-P.
"Dramatic," Rehan muttered. Yet, his curiosity was piqued. Salim wasn't the type to ask for help without a damn good reason. And the fact that he used binary—Rehan's native tongue—was either a tribute or a calculated intellectual lure.
Click.
Rehan pressed the button to release the magnetic lock.
Salim stepped inside, the blast of frigid, server-cooled air greeting him instantly. He surveyed the room—a chaotic web of LAN cables, stacks of discarded hard drives, and cyberpunk posters plastered over every available inch of wall space.
"Cozy den you've got here, Han," Salim remarked casually, as if he were stepping into a high-end cafe rather than a hacker's nest. "The temperature is perfect for preserving corpses. Or servers. Same thing, really."
"You have three minutes before I kick you out," Rehan said without preamble, swiveling his chair to face Salim. He didn't offer a seat. "And I hope you're not here to ask for a Math grade hack. Because we both know you don't need it."
Salim chuckled, dropping his backpack onto the floor and perching himself atop a discarded CPU casing in the corner—completely ignoring the etiquette of being a guest.
"Grades are fleeting, Han. I'm here for something... more eternal," Salim said. He reached into his pocket and pulled out a magnetic library card. It was worn, the edges peeling away.
"A library card?" Rehan arched an eyebrow. "You want me to wipe your late fees? That's petty, Lim."
"No." Salim shook his head. His eyes met Rehan's with a different kind of intensity. The gaze of an architect looking at a building's foundation. "I want you to help me create a 'Ghost'."
"A Ghost?"
"I've been studying the RFID (Radio Frequency Identification) system in our library," Salim explained, his voice turning clinical. "Every book has a chip. Every time a book passes through the sensor gates without being scanned at the librarian's desk, the alarm triggers. The logic is simple: If Tag Detected AND Status Not Checked-Out, THEN Alarm ON."
"Standard," Rehan interrupted, bored. "A middle schooler understands that logic."
"True. But I found a flaw in the algorithm," Salim continued. He grabbed a whiteboard marker from Rehan's desk and began scrawling a probability formula across the glass partition.
"The system has a 0.5-second processing delay for database verification. If two signals enter simultaneously with slightly shifted frequencies—one original, one ghost—the system glitches. It reads the book as having exited, but the database status remains 'Available.'"
Salim looked at Rehan. "I've calculated the frequencies mathematically. But I need you for the execution. I need you to write a script that can 'duplicate' this card's signal in the system, making it appear as if someone else is checking out a book at the exact millisecond I walk through the gate."
Rehan went silent. He stared at the formula Salim had written on the glass. It wasn't computer code; it was pure mathematics. Wave calculation. But when translated into machine language... it was brilliant.
"What for?" Rehan asked, his eyes narrowing. "What are you stealing? The Encyclopedia Britannica? Or is this just a prank?"
Salim leaned his back against the wall. His face returned to its flat, unreadable mask.
"Consider it a scientific experiment," Salim answered. "I'm just curious, Han. In this increasingly digital world, how easy is it to manipulate reality? If the system says the book is on the shelf, but the book is actually in my bag... which one is true? Physical reality or data reality?"
Rehan stared at Salim. He saw something familiar in the other boy's eyes. Loneliness. Not social loneliness—they both had friends—but an intellectual isolation. The loneliness of seeing patterns that no one else could see.
Rehan swiveled his chair back to his monitors. His fingers began their dance across the keyboard.
"You need signal spoofing," Rehan muttered, entering his work mode. "I can write a simple Python script to inject a false signal into the library server. But I need your card's unique ID."
"1209-SALIM-IPA1," Salim provided instantly.
"Got it. And the target book?"
"Any book. Filosofi Teras will do."
Silence returned to the room, broken only by the rapid, rhythmic clatter of Rehan's typing. Salim watched him work. He didn't understand the syntax of the code, but he understood the flow of the logic. Rehan was building a bridge between Salim's mathematical theory and digital practice.
"You know, Han," Salim said suddenly. "Dani was right about one thing."
"What?" Rehan asked without stopping.
"You need friends. Not for gaming or partying. But because a brain like yours is dangerous when left alone," Salim said. "You need a counterweight. Someone to give you a purpose, so your skills aren't just wasted on hacking toilet CCTVs or pranking teachers."
Rehan stopped typing for a split second. The sentence hit home.
"And you think you're that counterweight?" Rehan asked cynically.
"Maybe. I have plans, Han. I have so many plans in my head," Salim tapped his temple. "But my plans are just abstract concepts without an executor like you. We are... an odd collaboration. I'm the software, you're the hardware. Or vice-versa."
"Don't compare me to hardware. I'm the kernel," Rehan corrected arrogantly, but the corner of his mouth twitched upward.
"Done," Rehan said five minutes later. He plugged a small flash drive into his machine, transferring the program.
He tossed the drive toward Salim. Salim caught it with reflexes that were surprisingly sharp for someone who rarely exercised.
"Plug that into the USB port behind the librarian's desk when she isn't looking. It'll autorun. Every time your card is scanned, it sends the dual signal. The system will assume it's a glitch and let you through without the alarm, while the book status remains untouched," Rehan explained.
Salim gripped the flash drive. It felt cold in his palm.
"Thanks, Han," Salim said. "You're not going to ask for payment?"
"Consider it an investment," Rehan replied, swiveling his chair to face away from Salim. "I want to see how far this 'reality experiment' of yours can go. But remember, Lim. If you get caught, I don't know you. And that drive self-formats in twenty-four hours."
"Fair enough." Salim stood up, adjusting his bag.
As he reached the door, he paused.
"Han," Salim called out.
"What now?"
"For the Study Tour... bring your laptop. I have a feeling we're going to need more than just a library script," Salim said. His tone had shifted—it was heavier, darker. It was as if he were discussing a war, not a vacation.
Rehan remained silent. Salim's premonition mirrored Alya's message from the previous day. The lives of our entire grade are at stake. Why were the smartest people around him suddenly becoming paranoid? Or perhaps, they were the only ones truly sane?
"I always bring my laptop. It's my life," Rehan answered.
Salim nodded and stepped out of the room. The magnetic door thudded shut, locking Rehan back into his silence.
Rehan stared at his empty monitor. He reopened the CCTV window. He watched Salim walk away down the deserted corridor.
"An odd collaboration, huh?" Rehan murmured.
He opened his desk drawer and pulled out his homemade Signal Jammer. He weighed it in his hand. He had only planned to bring it to annoy Dani by cutting his phone signal if he got too loud on the bus. But after Salim's visit, Rehan felt he needed to upgrade its range.
He turned back to his computer. He began to type a new string of code. Not for the library, not for Alya. For himself. An offline GPS-based signal mapping program.
"If physical reality and data reality collide..." Rehan whispered, echoing Salim's words, "...I want to make sure I'm the one holding the remote control."
Outside, night had fully claimed Rajawali High. The evening wind howled, shaking the ancient banyan trees in the schoolyard. The rustling of leaves sounded like whispered warnings.
Unbeknownst to them, the wheels of fate had already begun to turn. Salim with his logic, Alya with her intuition, and Rehan with his code were unconsciously preparing their loadout. They were building a firewall before the actual virus attacked.
And that "virus" was currently sitting comfortably in the Principal's office, smiling warmly as he held the newly approved Study Tour proposal. The virus wasn't a line of code; it was a sinister plan wrapped in a gold ribbon titled "Character Building."
Rehan didn't know that the small script he gave Salim—the "Ghost" concept—would one day become the only way for Salim to deceive the tracking tablets on the Island of Death. That the minor experiment in the library was a dress rehearsal for saving their lives from the bombs planted in the old structures.
This odd collaboration had just laid its first stone.