The dig site was set close to the huge grey rock outcropping on the far side of the lake, not a long journey. They packed some archaeological equipment, weapons and armor, and flew across the lake on their grav bikes, landing at the southwestern tip of the rock within a few minutes. Here they found three cave mouths, perfectly cut and obviously not natural, the forest in the immediate vicinity of the caves burnt away to make space for a large, obviously abandoned camp. They set their grav bikes down at the edge of the camp site and moved into it carefully, weapons ready as they crept among the abandoned tents. In the entry to one of those tents they found the lockers of nine people who showed no signs of having returned to the camp after their ill-fated expedition. Foodstuffs were packed and eating utensils cleaned and stacked, a computer terminal in standby mode and beds made. They had clearly left their camp for a day’s work and simply never returned. There were no tabulae in the camp and no notes, so no way to find out what progress the archaeologists had made on the dig, or if they had any forewarning of whatever had overcome them. The only tabula that had been left behind must be the one that the Sogoi had picked up when they found Lavim, unconscious at the edge of the camp. With no clues in the camp, they had no choice but to enter the rock itself. While Saqr called back to the shuttle to tell Lavim what they were doing Al Hamra, Olivia and Adam returned to the grav bikes to change out of their dhoti and kameez and into light protective clothes, heavier grey jackets and leggings braced with light armored plates. They began to sweat as soon as they were dressed again, and by the time they returned to the cave mouth carrying their weapons and ammunition they already looked weary.

  “Which one?” Adam asked, nodding at the three cave mouths.

  “Lavim says they all go to the same tunnel,” Siladan told him, shouldering a pack of archaeological gear as he began to move forward. “But they used the middle one.”

  Adam grabbed him by the shoulder as he advanced, shook his head and took the lead position. Siladan walked behind him, hand on his sword, and behind him Al Hamra and Olivia walked cautiously, carbines slung low. Dr. Delecta and Saqr took up the rear, holding hurricane lamps that cast a cold, unwelcoming glow across the smooth, perfectly formed walls of the cave.

  They walked a short distance downward, the air growing noticeably cooler as they moved. The tunnel walls and ceiling formed a perfect oval shape that had been machined with such precision that it remained the exact same height and width as they descended. Siladan wanted to take out instruments to measure it but Al Hamra forbade it.

  “I think this place is perfectly cut to the nanometer scale,” Siladan protested, but Al Hamra waved his request away.

  “Nobody cares, Siladan,” Saqr whispered from behind him, voice pensive and her usual appetite for risk completely undetectable. “We’re here for monsters, not science.”

  They found the first body a little further down the tunnel, perhaps twenty meters from the entrance, collapsed against the cave wall with an accelerator pistol and a tabula lying on the ground nearby. The body was desiccated and pale, wearing the same uniform that they had seen Lavim Tamm trying to hide in his hostel room on Coriolis. The uniform was crusted with dried blood around its chest, from which a third arm had erupted, tearing the cloth of the overalls and rending flesh and bone apart in its eruption. They recoiled in horror at the sight of this strange monstrosity, everyone stepping back in disgust. After a moment to try and understand what they were seeing, Adam approached and carefully inspected the arm. It was not fully human, grey-skinned and vaguely scaly, with a contorted spine of some kind sticking out of its elbow and only three clawed fingers on the end of the limb. Although it had torn the victim’s chest apart when it emerged from the body, it was also clearly connected to and part of the body. The body had desiccated but had not decayed, as if even bacteria and insects knew better than to enter this place.

  They looked at each other with growing unease. “Is this sentinel work?” Adam asked, glancing back to Siladan, but Siladan shrugged helplessly.

  “I only read about them in books, Adam,” he replied. “Images of the aftermath of their attacks are, um, understandably rare.”

  “Let’s go on,” Al Hamra ordered. “We can search this on the way back. Stay cautious people.” Following his urging, they moved forward again, walking even more slowly down the sloping tunnel towards the middle of the hill and the fateful cavern.

  They found it soon, a large chamber formed in the same smooth, perfectly-made style as the hallways, but for six columns set in two rows, one near each side of the cave. As they advanced they saw more bodies scattered around the room, and a pile of rubble beneath a partially-ruined wall at the far end of the room. Although that end of the chamber was dim in the torchlight it was clear that the frieze Lavim had been working on, which their found footage covered, was at that end of the room, and that nothing else moved or lived in here. They inched forward.

  The second body was lying against the first pillar they came to. He had dropped an accelerator pistol on the floor next to what was once his right leg. The overalls of this leg were torn and shredded, and the leg changed near the hip into a tight bundle of tentacles, now dead and desiccated. From the bullet wounds in the tentacles and the leg itself it appeared that the dead worker had been shooting his own leg, trying to destroy the tentacles. The tentacles had rough suckers lined with hooks, and it looked as if he had been strangled by at least one of them at some point, because his neck was marked with contusions and tears of the same shape. It was unclear if he had died from the self-inflicted gunshot wounds or the strangling. Again, it looked as if the tentacles had extruded from his leg as if naturally part of it, but had at the same time injured him as if he had been dismembered. Adam checked the pistol, finding the magazine empty, Siladan labeled the man’s tabula with a small sticky note, and they moved further into the room towards the pile of rubble at the far end.

  The rest of the dig team had died around the frieze, two of strange transformations and the rest from gross physical violence. One, lying near the center of the chamber, had had her neck elongated like a rubber band so that her head flopped on the floor, and all the fingers on her hands stretched like they were made of rubber; the other had a hugely distended belly and neck, and appeared to have died of choking.

  “I think we heard these two on the film,” Adam observed in a dispassionate, detached voice, standing with his weapon ready as Dr. Delecta performed a cursory investigation of the bodies.

  One of the dead had been shot several times in the chest, and the remaining three had been eviscerated. One near the frieze appeared to have been stabbed from behind by a huge impaling weapon of some kind, tearing open much of his chest and causing him to drop an accelerator pistol, a mysterious cube-shaped object, and a tabula. The other two lay near the right hand wall, where they had been torn into pieces by some huge force. Though they shone their torches around the room they could see no sign of whatever had committed the horrific violence before them.

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  “Don’t touch the cube,” Al Hamra ordered everyone, gesturing at the fallen body of the man who had been recorded on the video shooting the guard. “We take it last. Let’s check the wall.”

  Siladan was already there, running his fingers over the tiles of the frieze and shaking his head in disgust at the damage the dig team had done. It was a Firstcome mosaic, made of small tiles in mostly silver and grey with occasional insets of gold and jewels where stars and planets might have been. Covering the entire rear wall of the cave, it appeared to show a stylized map of the Third Horizon on one side, and some other star cluster on the other. Unfortunately the dig team had torn down almost all the tiles that depicted the other star cluster, digging through the frieze to open a small chamber hidden in the wall. The gold- and jewel-inset tiles that had mapped that other cluster were scattered haphazardly across the floor of the cave, many of them broken or scuffed. It would be impossible to reassemble the mosaic without years of work and access to the best imaging and computing software of the Foundation itself.

  “Is that …” Saqr asked, staring at the wreckage of the left hand side of the wall in amazement.

  “A map of another Horizon?” Siladan finished for her. “I think so.” He stepped forward and placed a finger on one remaining tile, in which a perfectly-shaped diamond represented a burning bright star. “These vandals have wrecked a star map to another Horizon.”

  “Maybe that’s where your Empty Portal goes,” Al Hamra said, but Saqr shook her head.

  “You can take any Portal to anywhere if you know the coordinates and you can plot the path,” she reminded the Mystic.

  “And this wall maybe had the coordinates, or the path,” Siladan almost whispered, tracing his finger along a broken thread of silver that might have reached across to the Third Horizon if its path across the wall had not been torn up to open the hidden chamber. He pulled the remnants of the silver wire, but it had been torn out and it was unclear where in the Horizon it ended, the filigree work on the frieze too delicate and subtle to determine exactly where it had been embedded. “Vandals,” he hissed.

  “Was it deliberate, do you think?” Dr. Delecta asked.

  “You mean to destroy the map?” Siladan asked, and shook his head. “This map would be worth a fortune, you could found a new Faction with this map alone. They must have not understood it.” He cursed. “Maybe they took pictures?” He turned to the others, holding the silver thread in one hand. “This would be an incredible discovery. History-changing. This thread!” He snapped it in disgust.

  “Was the Sentinel here to defend it?” Saqr asked. “Maps of the Portals are older than the Firstcome, but this is a Firstcome picture?”

  Seeing her confusion, Siladan shook his head. “I doubt it. The cave is older. They maybe put the map here to preserve it, knowing the cave would last forever.”

  “But why put a valuable map like this in a place guarded by things they can’t control?” Saqr asked. “It might kill them when they came back to find it.”

  “Maybe that’s the reason,” Olivia suggested. “Maybe they didn’t want people to find this map.”

  Everyone looked at her. “What are you suggesting?” Al Hamra asked finally.

  “Remember the Order of the Pariah formed to destroy the Portals back to the First and Second Horizon. The war to destroy them was so violent that it disrupted the Portals and started the Long Night.” She looked around at them. “Why would you want a map to go back to the Horizons you tried to cut yourself off from?” She stepped closer, examining the map of the Third Horizon, then turned to face them with a shrug. “Maybe they wanted to have a map of their enemies, but wanted to make sure that it was well guarded, in case people who weren’t supposed to find it came in here.”

  “People like us?” Saqr suggested.

  “Maybe the mistake was taking film,” Olivia replied. “If I wanted to preserve a map but didn’t want anyone to see it, I would bury it in the back of a cave guarded by –“ she counted the columns performatively with one finger “– six Sentinels, that are triggered either by that box, or by the act of filming.”

  “Why would you hide things behind it?” Saqr asked, pointing to the chamber.

  “Maybe that’s what the Sentinels were here to stop,” Siladan suggested. “Maybe whatever was behind the wall was more dangerous than whatever was written on the wall.”

  “Maybe …” Olivia paused, looking around. “Lavim found the statuette in here, right?” She asked, looking to Al Hamra for his nod of confirmation, “And Siladan learnt that the statuette contains memories, either Firstcome or maybe even Portal builder. So…” She pointed at the wall. “Here we have a map the Firstcome painted that points back to their enemies, who they almost crashed the Third Horizon to defeat. What if the wall is just a picture, and the statuette contains the detailed information about how to get back to the First Horizon?” Seeing Siladan’s nod, she added, “Imagine, it might contain a memory from a Portal builder or a Firstcome, with coordinates, entry paths, and Portal locations. So you bury it here, and the map on the wall tells a clear story about what it holds.”

  “A story in pictures, that will last longer than language itself,” Siladan concluded, “And if anyone opens the chamber incorrectly, the Sentinels kill them.” He looked around at the pillars. “You think these are the Sentinels?”

  Olivia shrugged. “Do you see anything else in here? And they don’t touch the ceiling.” She pointed to the top of the pillar, which rose to just a few centimeters short of the ceiling. “It could be a giant trap, with a final warning on the wall that will be clear to any civilization in the Third Horizon that understands space travel.”

  “Not a very effective warning,” Adam pointed out. “These idiots ignored it.”

  “Probably better not to make your warning out of gold and silver,” Al Hamra added. “Look,” He pointed to a box near the wall. “What’s that?”

  “An artifact case,” Siladan said, approaching the box cautiously. It was a small suitcase-like container, open on the ground in front of the wall, with a few small objects in it. Moving closer, Siladan made out two flat stones about the size of the palm of his hand, placed next to each other on the foam backing of the case, and a pair of spectacles with simple bent wire temples and a strange arrangement of several layers of hinged lenses. He moved past the case to look into the hole in the wall, where the tiles and parts of the wall had been chipped away. It was carved in the same perfection as the walls and ceiling of the cave itself, penetrating inward from the wall in a perfect oval. Before it was covered over with the mosaic it might once have been an alcove in the original cave. “I think this was part of the Portal builder ruin,” he called back to them. “These things must have been inside it.”

  “Let’s take them and go,” Saqr suggested, standing back near the entrance. “I think we’ve seen enough. This place is cursed.”

  “I agree,” Al Hamra said. He moved over to the body of the dead man who had dropped the cube, looked at the cube carefully and then drew out a small leather bag, which he kicked it into with one toe. He picked up the man’s tabula and then turned to Siladan. “Siladan, you bring the artifact case, don’t touch anything inside it. Adam,” he said to the soldier as he picked up the discarded gun from next to the tabula, “You cover us. Olivia, you too. Siladan, on my mark.” He waited until Olivia and Adam were at the tunnel entrance with carbines ready and then counted down, while Dr. Delecta and Saqr waited anxiously just inside the tunnel, Saqr with her weapon out and Dr. Delecta pointing a torch into the room.

  Siladan grabbed the case and started shuffling back to the tunnel entrance, Al Hamra moving cautiously alongside him. Nothing moved. They reached the tunnel entrance and stepped back into it, moving behind Saqr, who backed away after them followed by Dr. Delecta and then Adam and Olivia, Dr. Delecta’s torch shining into the room as they moved away. The pillars cast stark shadows from her torch onto the far wall, but none of their movements were unexpected. They retreated slowly up the tunnels towards the welcoming heat of the surface, leaving the dig crew to mummify, abandoned in the terrifying dark.