They moved faster now and reached their destination twenty minutes later. Dusk was creeping into the sky and the flood had subsided a little when they arrived over the point Vox had been aiming for. The dwindling light showed them that they would have to wait until the water had sunken lower.
Vox busied himself with guiding their brothers towards them. Apart from his occasional comments, the two Astartes stood silent guard over their mortal.
When the night had fallen fully, Titus descended into the canyon first. The water only reached to his waist now and he called the others after him.
To avoid using the jump pack yet again, Vox decided to climb down. Solomon on his shoulders, he started the descent. It went well for most of the way. The flood had knocked all loose stones away and only the steady rushing of the water could be heard until Vox slipped and fell. From this height, he should have rolled to compensate for the momentum but to protect the legate, he was forced to land on his feet instead. The displaced water smashed back into them in a great splash before the silence was back. In shock, Solomon had slung all appendages around Vox’s helmet. He uncurled them when Vox gently patted his knee.
“You alright?”, the black shield wanted to know.
“Just wet”, Solomon replied bravely. Titus disbelieved him. Surely, he had been caught between Vox’s shoulder guards. His thighs would be heavily bruised.
Down here, it was dark. There was nothing to see but raw stone walls and the soft reflections of starlight on the water around them.
“This is it?”, Solomon asked a little uncertainly, rubbing the burn mark on the left side of his face with his mechanical hand. He started to shiver in the cool air.
In reply, Vox slowly walked up to a part of the wall that looked no different than the rest of the canyon. He gently took Solomon’s organic hand and guided it to a point at head height for an Astartes.
“Somewhere here”, he informed him.
“Ah, yes”, Solomon said, leaning forward. “This must be the lock!” His fingers danced searchingly over the stone for a moment then, he took out the ominous key from the Dark Age of Technology. The legate turned the cube over a few times and looked closely at the hole.
“I will need light. Are we alone?”, Solomon wanted to know.
“Yes”, Vox confirmed after a few heartbeats.
A bright, circular light went up to illuminate the scene. Under it Solomon continued to turn the cube this way and that, inspecting it minutely. His scar rippled oddly as he grimaced in thought. Vox meanwhile had bowed down and leaned his head against the wall to bring the man as close to the lock as possible. Titus had to hide a smile. Seeing them working together as politely and smoothly as this was almost endearing.
“What are you doing?”, Titus inquired of the legate.
“I’m checking if there is a direction in which the cube is meant to be used”, Solomon explained. “I don’t want any self-defence measures going off if I slide it in wrong. This should be it.” He pushed the cube into the wall.
There was hardly any noise. A hollow clicking, a quiet scraping when the door opened, followed by the sound of the water coming in.
“I hope they made whatever is in there waterproof”, Solomon said.
“Well, they made the door waterproof”, Titus reckoned and followed Vox inside.
The initial corridor was short. Beyond it they entered a circular room.
In the light Solomon had left on, they made out a simple but delicately cut relief on the smooth, rounded wall. All of them recognized what it showed immediately. Even though the landmasses looked a bit different than they had come to know them, there was no doubt about it: It was an image of Terra.
A panel protruded from the swirling water in the middle of the room.
“That looks like an elevator”, Solomon said. “And I don’t think it’ll go up.”
Vox nodded, took him off his shoulders and handed him to Titus like someone would hand around a child. The water had sunken under waist height now but, for the human, this still meant sinking in to his chest and there was a current, even noticeable for someone with the weight of an Astartes.
“Give me the lamp”, Vox demanded softly and got it as soon as Solomon sat safely on Titus’ left shoulder guard. They lost no words about Vox going down there alone. He was the one with a working helmet and could still vox underwater. One of them had to stay up here to protect Solomon.
Calmly, the librarian walked up to the panel. It lit up by itself even as he came close and showed a few mystic signs. Vox laid his hand on one and the floor beneath him started to sink down slowly. Titus braced himself. As he had anticipated the current increased suddenly when the elevator had sunken beyond the thickness of the floor. Vigorously the water streamed through the widening gap while the platform became a circular waterfall with Vox sinking down in the middle.
In his armour, a Space Marine was heavy enough to walk underwater. For a moment, they saw the light he carried flicker and reflect in the swirling current. Then, it went away.
They waited in silence, the water line dropping lower and lower. After a long while, the circular waterfall got quieter and finally stopped. Whatever space was down there, was now filled with water. Left in the upper room was just a waterline that reached lower than Titus’ knee and thus he put the legate down. The man straightened his clothing, waded between him and the wall and said nothing, just waited patiently, shivering in the cold.
“I’ve reached a corridor full of doors”, was the first they heard from Vox. “If there is a machine spirit in here, I can’t find it. Want me to use force?”
Titus saw Solomon shake his head and passed on the negative.
Again it took a while until Vox came in. The water was just knee-high for Solomon now.
“I’ve reached a room with a pillar in the middle”, Vox told them. “It’s about fifty paces across and has small compartments along the wall. They are at about chest-height for me. I don’t see another exit.”
On a signal of the legate, Titus knelt down next to him and opened the channel so he could talk to Vox directly.
“Look at the pillar, please”, the man said and, in the sparse light that filtered in from outside, the expression of his burned face suddenly got intense.
Vox was quiet for a moment.
“It is about a metre in diameter and made of the white stone outside. Looks like a natural formation. What am I looking for?”
“For any kind of switch, button, panel or opening”, Solomon said.
Again, there was silence for a minute.
“A part of the pillar can be rotated”, Vox informed them. “There is a cube in here. It is clamped into some kind of holding mechanism.”
“Describe it, please!”, Solomon asked.
“From the bottom and top of the compartment protrudes a triangular bar each. It splits in three and this way clamps the cube, which is standing on its points. Does that make sense to you?”, Vox inquired a little uncertainly.
“Yes, absolutely!”, Solomon assured him with conviction. He must have been expecting something like this. Titus could not readily imagine what Vox had just described.
“How big is the cube?”, the legate wanted to know.
“About my index fingertip to thumb edge length.”
“And four of its points are not clamped?”, Solomon checked.
“Then try putting a finger to each unclamped point and rotate it in the same direction you rotated the pillar!”
“On it”, Vox confirmed. There was another pause.
“Alright, I got it, but I have bad news for you. You have company inbound. Don’t make noise anymore, I’m coming up.”
Titus stood up and put the microbead of his gorget in his ear so that transmissions would not be heard out loud anymore. Solomon sidled up to the wall again. They waited.