Rain fell over Jakarta as if someone were dumping the contents of the sky onto the apartment windows. From the twenty-first floor, the vehicle lights on the road looked like streams of lost fireflies weaving between the buildings.
Senja Adira paid no attention to the view. She was counting rope.
"Two hundred forty-six meters," she said.
She pulled the end of a red static rope from her bag, checked its knots, then coiled it neatly again. On the living room table, the cave exploration gear covered nearly every inch of space: helmets, headlamps, gloves, knee pads, compasses, communications gear, a first-aid kit, a waterproof camera, and two small tubes of marking chalk.
Ucok sat cross-legged on the floor, arranging batteries inside a transparent case. His expression was stern, almost always making him look like someone who had just turned down a bad offer. Yet he arranged the batteries with such care, as if they might take offense if placed carelessly.
"Sen, I'll separate the spare batteries, okay? The new ones are for the main light, and the old ones for the radio," Ucok said. His Javanese accent was still audible, even though he had spent most of his childhood in Lampung.
"Good. Don't mix them with the camera batteries. The voltage is different."
"Lha, I'm your friend, not some Boy Scout kid. I know, okay."
Oscar sat on the floor behind a pile of field gear. He was preparing Senja's equipment: the headlamp, gloves, knee pads, and waterproof camera had been arranged in small groups so they could be checked again easily.
Beside him lay a large map of Luweng Ombo Cave. One corner was held down by the first-aid kit, while Oscar's finger traced the passage lines branching off from the main route.
"My name is Oscar," he said without looking up. "Not Osveldo. Oscar means a victory trophy. It has meaning."
Ucok looked at the equipment in front of Oscar, then turned to the map. "Kowe iki getting the gear ready or reading the map, ta?"
"Both. I'm making sure Senja has everything she needs and that we don't enter the cave like a lost tour group."
Oscar moved his finger along the lines on the map. The floor plan showed the mouth of Luweng Ombo Cave, the sharply descending main passage, and several narrow side passages that ended at X marks. At the very bottom, a winding blue line disappeared toward the south.
"Look at this," he said. "The watercourse isn't marked on the latest survey map."
Senja stopped what she was doing and came closer. She traced the blue line on the map with her fingertip, then nodded slowly.
"You're right, Oscar. This watercourse isn't marked on the latest survey map."
Oscar smiled in satisfaction. He lifted the map slightly off the table, revealing its aged surface. The paper had yellowed, its edges were brittle, and damp stains spread across several sections like shadows frozen in place. The passage lines had been drawn in brownish ink, while the underground watercourse was marked with blue ink that had begun to fade.
In the lower corner of the map was a mysterious eight-pointed sun ornament. At its center was a circle containing intricate carvings, resembling an eye watching from behind layers of stone. There was no explanation anywhere around it, as though the mapmaker had deliberately left its meaning hidden.
Senja picked up the map. Its paper had yellowed, its edges were brittle, and several sections were covered in damp stains. The eight-pointed sun ornament was in the lower corner. Senja recognized a similar shape. She had seen it on a copy of the travel notes of a Dutch surveyor, though the carving there had been simpler.
Luweng Ombo was more than a hole in the rock. In ancient times, the place had been treated as a boundary. Anything brought there and considered to carry evil was not destroyed, but locked away.
Below that paragraph was a drawing of a winding watercourse. Its line entered through a black circle, descended deep underground, then ended at a wave symbol.
The Indian Ocean.
Ucok moved closer. "Iki really a historical record, ta? Not just local folklore?"
"Both could be true," Senja replied. "Historical records often leave out the parts people weren't brave enough to write down."
Oscar leaned against the table. "That's what I've been trying to tell you. The relic didn't disappear. It's locked at the bottom of Luweng Ombo. Its power flows through an underground watercourse all the way to the Indian Ocean. If this legend is true, we're not looking for an ancient relic. We're looking for something that was deliberately hidden from the world."
Senja reread the final sentence. Beneath it were deeper pen marks, as though the writer had hesitated before adding a note:
Do not open the door chosen by the water.
"We don't know whether the relic is evil," Senja said.
"If it was neutralized and locked away, what do you think it is?" Oscar cut in.
"Not necessarily evil. Maybe the people who used it were evil."
Oscar opened his mouth, ready to argue. Senja already knew that look. But before he could get a word out, Senja folded the book and slipped it into a waterproof pouch.
"The decision stands," she said. "We leave tomorrow morning. First stop: the village near Luweng Ombo. We'll verify the access route, the weather conditions, and our cave-exploration permits. No one touches anything until we understand the place."
Oscar raised one finger. "I have three objections."
"Save them for the trip."
"Fine. But if it turns out I'm right—"
"You can remind us until we're old."
Ucok chuckled. "Nah, that's a fair decision, kuwi."
Senja stood and checked the equipment list again. She led not because she was the most talkative, but because every decision she made had to bear the responsibility for the safety of two other people. That was why she never treated adventure as a thrill-seeking game.
She touched the compass beside the old book.
Its needle was not pointing north.
The needle trembled, then slowly turned toward the apartment window—to the south, toward the sea.
Ucok noticed it first. "Senja... is your compass broken?"
Senja picked it up. The needle immediately swung back north.
Then the old book inside the waterproof pouch began to vibrate.
Not loudly. Just one short pulse, like something inside had only just awakened.
Oscar stopped smiling.
Outside, lightning split the Jakarta sky. For an instant, the reflection in the window formed the shadow of a wet stone passage—even though beyond the glass there were only tall buildings and night.
The shadow vanished when the lightning faded.
Senja looked at her two friends.
"We're leaving earlier tomorrow," she said.
"Because of the weather?" Ucok asked.
Senja gripped the compass, which had returned to pointing north.
"Because there's something in Luweng Ombo that knows we're looking for it."