Seru’nai turned, the glow of their markings casting a soft radiance along the walls as it led them deeper into the tunnels. The air grew steadily warmer, tinged with a smell of mineral dampness and the faint scent of burning oils. The tunnel widened, revealing several smooth terraces carved into the stone, each one lit with a dim, golden glow. The away team followed Seru’nai around a final bend, and the tunnel opened wide before them.

The cavern was so vast it defied comprehension. Shafts of impossible daylight cascaded down from the roof high above, striking the facades of hundreds of small dwellings that had been carved into the cavern’s walls. Long rope bridges criss-crossed the open space, glimmering faintly with the threads of some bioluminescent thread, like some large, chaotic spider’s web.

Dozens, or perhaps even hundreds of people, moved about the terraces. Pale and elegant, like Seru’nai, their movements were slow and deliberate, their garments flowing like moving water. The chamber seemed even to pulse faintly with life. Light that dimmed and brightened in rhythm, and somewhere deeper still, voices raised in melodic harmony could be heard.

Lieutenant Junior Grade Irovin’s voice was the first to break the team’s awed silence. “It’s a whole civilization. Underground.”

T’Luni’s tricorder hummed softly. “There are approximately one hundred and forty life signs within the tricorder’s scanning radius.”

Seru’nai turned back to them, their eyes flashing as they caught the light. “You walk in the Heart of the Stone now.”

The descent into the settlement felt like a dream. Every sound seemed softened by the stone walls around them. The murmur of voices, the whisper of bare feet on smooth stone, and a sound of rhythmic chanting that seemed to come from somewhere unseen.

As they followed Seru’nai through a winding corridor that curved its way gracefully down along the wall, inhabitants of the settlement stopped and turned to watch them pass. Their expressions were unreadable, more distant than hostile, as if looking upon something sacred or forbidden. A few touched their foreheads as the away team walked by, whispering words that the translator rendered as “Surface-Walkers”.

Irovin leaned in towards T’Luni’s shoulder. “They keep calling us that. I’m not sure if it’s a good thing or not.”

“It is hard to deduce meaning from a single word,” T’Luni replied. “But their tone suggests reverence, not fear.”

At last, Seru’nai brought them to a stop in front of a large archway, framed by more intricate carvings. At the top was a large keystone with a deep spiral cut into it, and each of the stones from that one to the floor had a kneeling figure with its arms outstretched towards it. Beyond the threshold lay a chamber illuminated by a soft blue light, with stone floors that had been polished as smooth as glass.

Seru’nai then led them through this archway into the room beyond, where three figures waited at the opposite end of the chamber, standing on a raised dias of smooth black stone. These three were robed in the same style of garments as the others, but theirs were richer in colour, and adorned with small metallic objects and emblems that shimmered when they moved. Their skin bore more pronounced luminescent patterns than Seru’nai’s – flowing from their temples and down their arms like growing script. Their eyes reflected the chamber’s light with an eerie intensity.

Seru’nai bowed deeply and spoke in the melodic cadence of their language. The Universal Translator struggled again for a moment, then rendered: “Great Voices. These are the surface-walkers who came through the gates. They are seekers, not destroyers.”

One of the Elders, who was tall and thin with long white hair, inclined their head slightly. “Do you speak for them, Saru’nai?”

“I do.”

The Elder turned and gazed at the away team. “Then you bear their burden.”

Cruikshank took a cautious step forward and bowed awkwardly before he spoke. “We come in peace. We are explorers – scientists. We discovered your home while we were surveying the surface.”

“Surveying,” repeated another of the Elders, this one has glowing tattoos that traced their cheekbones. “You walk where the Old Voices walked, and you call it surveying?”

The first Elder lifted their hand, silencing the others. “We mean no disrespect to the surface-walkers. You are known to The Stone – it woke when you came.”

Irovin frowned. “It woke?”

The Elder turned their gaze upon her. “The light followed you, did it not? The air shifted with your breath? The Stone knows when its children return.”

Cruikshank exchanged a glance with T’Luni. “We have noticed… unusual environmental changes since we entered the tunnels. Are you saying the structure itself is alive?”

The Elder shook their head. “Not alive, no. The Stone remembers. It holds the echo of the one who waits beneath.”

The third Elder, the smallest of the three, spoke softly. “Its name is not to be spoken to the surface-walkers.”

A low murmur rippled through the chamber, a sound like distant wind through hollow places. Then silence fell again.

The Elders beckoned Seru’nai forward, then the four of them closed into a huddle, their chorus of melodic voices too soft and distant for the translator to pick up what they were saying. After a long while, the huddle broke, and Seru’nai turned back to the rest of the away team.

“The Elders wish to offer you rest and food. You may stay until the sun above forgets you, and then perhaps, you may be allowed to see what the Stone remembers.”

Cruikshank hesitated for a moment, then nodded. “We would be honoured.”

Seru’nai led them back out of the temple and back along the wall’s gently curving path until they were several levels up from the temple, then across one of the countless rope bridges to a small dwelling. “This space has been made available to you, as our honoured guests. Our people are already moving to gather your belongings and bring them here.” They pushed the wooden door open and held out a hand, inviting them to enter. “I will return for you when the feast is ready.”

The door closed behind them with a soft, resonant thump, and just like that, they were alone again. Craig crossed the room, taking a seat cross-legged on one of the pillows that surrounded a low wooden table. His open tridorder was in his hand, its soft beeps echoing faintly off the curved walls. “I’ve been running a scan since we left the temple,” he said, “These readings don’t make sense. The entire place is resonating at a subsonic frequency, somewhere around 11 hertz. I think it’s more than a geological phenomenon.”

T’Luni looked up from her own PADD. “Do you suspect it is artificial?”

He nodded. “Partially. Maybe a natural cavern network that’s been augmented somehow. Perhaps reinforced with conductive minerals or some kind of piezoelectric lattice. The way the light responds to us could be a feedback system that reacts to bioelectric signatures.”

Tanna leaned against a wall, arms crossed. “Do you mean to say that the walls are watching us?”

“Not exactly,” Craig said, though his tone didn’t sound confident. “More like… listening.”

T’Luni tilted her head thoughtfully. “An environmental system that is attuned to sentient presence. It would explain the synchronization with our circadian rhythm.”

“Should we try to let the Erikson know what’s up?” Tanna asked.

“I can’t see any harm in it,” Craig responded. “The worst we’ll get is static.”

Tanna tapped her commbadge. “Away Team to Lief Erikson. Can you hear us?”

There was a hiss of static, and her shoulders dropped a little in disappointment before the voice of Commander Saberwyn rang out through the room, sharp and clear.

“Loud and clear, Lieutenant,” He said. “We’ve been trying to get a hold of you for a few hours now. What’s going on down there?”

Tanna looked disbelieving at T’Luni and Craig before responding. “Better than expected, sir, actually. We have made peaceful contact with the subterranean civilization. They are humanoid, technologically limited, but architecturally advanced. The atmosphere is stable and the team is safe. But there’s something… weird about this place. The comm interference we were having before has just, I don’t know, vanished.”

“Vanished?” Saberwyn responded, “Have you activated any equipment?”

“No, sir,” T’Luni responded. “It seems to have coincided with the completion of a brief cultural exchange with the leaders of this settlement.”

There was a pause, then Commander Saberwyn’s voice returned. He sounded cautious but intrigued. “Understood, Lieutenant. Let’s hope we get to hang on to our signal. Keep us up to date.”

“Copy that, sir. Away Team out.”

There was a knock on the door, but before anyone could respond, it swung open. Seru’nai was framed in the doorway, tall and composed, their eyes reflecting the chamber’s amber light. They smiled, and almost serene, reverent expression.

“The Elders have spoken,” they said softly, “Tonight, we shall hold the Feast of Harmony, in your honour.”

Tanna blinked. “A feast? For us?”

“It is tradition,” Seru’nai replied. “When the Stone welcomes new voices, we celebrate its song.” Their gaze turned to T’Luni, resting there for a moment. “You may sit next to me, if you wish. The Elders believe the Stone hears you most clearly.”

T’Luni inclined her head in quiet acknowledgement. “That would be… acceptable.”

Seru’nai bowed. “Then come. The feast awaits.”