Morning came without sunlight.
Fog hung low over the village road, veiling the rice paddies and trees in grayish white. The vehicle carrying them stopped in front of a wooden roadside stall that had just opened its doors. The latest Land Rover Defender 90 from the classic series looked dirty from the long journey, but it still stood proud amid the wet road and limestone hills stretching like the backs of enormous sleeping beasts.
They had taken the overland route from Jakarta. After exiting at the Colomadu toll gate, they continued through Solo, Wonogiri, and then Pracimantoro before entering the border region of Jawa Timur and Pacitan. The route was relatively good and served as a main corridor for intercity buses, though several stretches between the hills had begun to narrow and wind.
Senja got out first. She checked the road, the tires, and the vehicle's rear doors, then stared at the line of hills in the distance.
“So Luweng Ombo is behind those hills?” Oscar asked from inside the vehicle.
“According to the old coordinates, yes,” Senja replied.
Oscar rested his head against the seat. “Nearly a full day's travel just to look at a hole in the ground.”
“Not an ordinary hole,” Senja said as she opened the rear door. “Luweng Ombo is the deepest vertical cave on the island of Jawa. It's about two hundred forty-six meters deep.”
Ucok turned off the engine and glanced back from the driver's seat. “Two hundred forty-six meters... if you fall, how many times do you get to regret it?”
“If the equipment is right, you won't fall,” Senja replied.
“And if the equipment is right but the person takes one wrong step?”
“Then we can't afford to take a wrong step.”
Oscar climbed out carrying the map tube. “Besides its depth, the passages run for roughly seven to seven and a half kilometers. The terrain is extreme. So technically, we're not here to look at a hole. We're here to enter a highly complex underground system.”
“Sampeyan could've said that back on the road,” Ucok said. “But all we talked about was what music to play.”
“I was keeping the team focused.”
“With dangdut?”
“Music is part of the strategy.”
Senja let them argue while she checked the ropes. Once everything was secure, she closed the vehicle's doors and leaned for a moment against the cold body of the Land Rover.
“Geographically,” she said, “Luweng Ombo is in Kalak Village, Donorojo District, Pacitan Regency. This area is part of the Sewu Mountains karst landscape. The limestone has formed vertical shafts, passages, underground rivers, and chambers that have developed over thousands of years.”
Oscar spread the map across the hood. “That's why this area matters. The Sewu Mountains are now recognized as part of the UNESCO Global Geoparks. Luweng Ombo could be considered a world-class underground laboratory.”
Ucok gazed at the hills shrouded in fog. “A laboratory whose door is that deep?”
“That's exactly what makes it interesting,” Oscar said. “Down there, there are watercourses, underground waterfalls, and ecosystems we can't see from the surface. Bird nests too, in some sections.”
Senja pointed to the contour lines on the map. “The main vertical shaft drops straight down. Once you reach the bottom, the route changes into interconnected passages. Water can point the way, but it can also alter the terrain without warning.”
“Where does the water flow?” Ucok asked.
“Old theories point south, toward an underground river system connected to the coastal area. But this map shows another route.”
Oscar tapped a winding blue line near the bottom of the map. “That's why ordinary surveys aren't enough. This line isn't recorded on the latest survey map.”
They had heard the history of Luweng Ombo cave exploration ever since the journey was still passing through Solo. The cave had been explored by various national and international caving teams. From the 1980s through the 1990s, foreign speleological teams worked with domestic cave explorers to map its depth, passages, and watercourses.
But according to Oscar, there was a part of the history that was rarely discussed.
“Official expeditions always leave reports,” he said. “But there was one expedition whose records were incomplete. A team from the Netherlands. They came under the pretext of conducting hydrological mapping, but some notes suggest they had another agenda.”
Senja looked at him. “They were searching for the ancient relic.”
Oscar nodded. “Not just some treasure-hunting story. They were looking for a relic believed to have been sealed at the bottom of the cave.”
Ucok shoved both hands into his jacket pockets. “Why would Dutch people come all the way to a cave in Pacitan just because of a relic story?”
“Because the story may have come from old archives,” Senja replied. “And maybe they knew something other explorers didn't.”
Oscar unfolded the map. In its lower corner was an eight-pointed sun ornament. At its center was a circle with intricate carvings, resembling an eye watching from behind stone.
“The relic they were looking for bore the same seal,” he said. “This is its sun-shaped ornament.”
The fog shifted slowly above the road. For a moment, the carving in the center of the ornament seemed to be truly staring at them.
Ucok stepped closer. “Kowe sure that's the relic's seal, not the mapmaker's mark?”
“I'm sure someone considered it important enough to hunt for.”
Senja took the map. The paper had yellowed, its edges were brittle, and damp stains spread across several sections. She remembered the old notes they had found in Jakarta: the relic had not been destroyed but locked away. Its power had been channeled through the underground watercourses so it could not return to the surface.
“If that Dutch team was really looking for it,” Senja said, “they may have already found another way in.”
“And if they did?” Ucok asked.
Oscar stared at the shadowed hills. “They may never have made it out.”
From inside the stall came the clink of a spoon against a glass. An elderly woman stood behind the wooden counter, watching them without saying hello. She was probably over sixty. Her hair was tied in a simple bun, and around her neck hung a small metal pendant shaped like an eight-pointed sun.
Senja noticed the pendant but did not ask about it right away.
They ordered coffee and wrapped rice meals. The woman served them with calm movements, as though three people arriving with cave gear were nothing worth questioning.
“Luweng Ombo Cave?” she said at last.
Senja nodded. “We're going to conduct a preliminary exploration. We've already contacted the village head.”
“You have.” The woman set three glasses of coffee on the table. “But the village head can't grant permission for a place that doesn't belong to him.”
Oscar lowered his map. “Administratively, the cave is within the village's territory.”
“The land might be.” The woman looked at him. “The water isn't.”
Ucok blew gently on his coffee. “What do you mean, Bu?”
The woman did not answer. She picked up a cloth and wiped the already-clean table, then looked toward the hills.
“The water from Luweng Ombo never follows the same path twice.”
Oscar opened his mouth, but Senja raised a hand.
“Is that based on the villagers' observations?” Senja asked.
“Based on the people who made it back.”
The words made the stall suddenly feel quieter. Outside, the sound of a chicken drifted faintly through the fog, broken and distant.
Senja took out a copy of the old map and spread it across the table. She pointed to the blue line leading south.
“We found a watercourse that isn't on the latest survey map.”
The woman looked at the sun symbol in the corner of the map. Her expression changed, only slightly, but enough for Senja to notice.
“Where did you get that drawing?”
“From old records.”
“Old records don't always mean records you're allowed to read.”
Oscar leaned forward. “You recognize the symbol?”
The woman picked up her own glass. Her hand did not tremble, but her index finger stopped directly above the sun pendant.
“Here, that symbol is called the Guardian Spring.”
“Guardian of what?” Ucok asked.
“The door.”
Oscar gave a faint smile. “A door inside the cave?”
“If all you see is stone, you'll assume every door is made of stone.”
Senja stared at her. “What's behind that door?”
At last, the old woman looked directly at Senja.
“No one knows. People in the old days knew only one thing: as long as the water still flowed to the sea, that door would remain closed.”
Senja let the words hang between them. Outside, the fog began to thin, revealing the road rising toward the hills. She folded the old map, put it back into the tube, and stood.
Oscar immediately picked up the equipment that had been leaning beside the table. Ucok drained his coffee in one gulp and reached for the car keys. None of them spoke about the door again, but all three understood that their journey had just become something far larger than cave exploration.
A few minutes later, the Land Rover moved on, leaving the stall behind. The road to Luweng Ombo cut through wet limestone hills, while ahead of them, beyond the dense trees and fog that had not yet fully lifted, a narrow path opened toward the cave entrance.