engines rumbled, casting out periodic whistles with blasts of steam. Glowing green oil pumped and bubbled behind clear crystal in tall bronze tanks. Giant valves slowly turned on their own, powered by steam or Promethean fire. Off to the right, a pipe screamed and burst into flames. Several other industrial torches blazed, cloaked in smoke.
“Look,” Mac said.
He pointed to the far right, to large open vats, full of shimmering black oil. Pipes ran from those tanks to a mud lake, which bubbled and burped with sulfurous gases. Upon the sludge’s hot surface shone pools of the same unrefined oil, apparently the source of fire-defying Promethean Blood.
One mystery among many solved.
Gray got them all moving again, especially considering what they still needed to do: find another way out of here. Or at least some way to put this city back to sleep.
Still, Hunayn’s warning played in his head.
If you wake Tartarus, know it will be for the last and final time.
With that ominous warning in mind, Gray headed through the massive foundry. He and the others had seen the handiwork produced by this factory out in the city. But in here, the Phaeacians had hidden their greatest endeavor, their masterworks.
The group treaded lightly across the foundry, as if fearful of waking the bronze colossi to either side. The figures stood ten stories tall, six to a side, encased in scaffolding, bridged by ladders. Though still works in progress, their shapes and countenances were evident enough. Six men and six women. A couple were horrendous in shape, multi-limbed and misshapen. Like some Lovecraftian beasts come to life, true Chthonian monsters.
“The Elder Gods,” Bailey murmured. “The Titans of Greek mythology. The twelve firstborn of Uranus and Gaia. Imprisoned by the gods who came later.”
“And still trapped here, by the look of it,” Maria said. “In a prison made of bronze pipes.”
Gray studied one, whose chest lay open. Within that cavity, green blood bubbled throughout a labyrinth of crystal pipes, setting the interior aglow. In the center was a gold and bronze spherical device, not unlike the astrolabe that led them here, but threatening in appearance, especially as it turned with a flash of flame, as if ticking downward.
He pictured this war machine—which he somehow knew it was—marching across a battlefield, its blood surging with radioactive fire, like some walking atomic bomb.
“We can never let this fall into the wrong hands,” Gray said. “Into any hands.”
Gray knew Hunayn must have felt the same a millennium ago.
But what did the captain do?
Gray hurried the group past the foundry, passing under the Titanic gazes of the Elder Gods, to where the cave ended at a small antechamber.
Two fountains of black oil—Promethean Blood—filled stone containers on either side, the excess spilling into catch basins on the floor and draining away. One vat was huge, a veritable Roman bath. The other was small, more like a washbasin.
Between them stood another bronze door, identical to the one behind them, but this one had a small window in it, set with a translucent stone, maybe polished crystal or a crude form of glass.
The view through it was cloudy, but details were clear enough, especially considering what lit the space. Beyond a small bronze landing in the next room stretched an Olympic-sized pool. It was flush to both sides of the chamber. Only this pool was full of Medea’s Oil. It glowed a toxic emerald, its surface vaguely stirring, as if hiding some new horror. While its depth was unknowable, considering the scale of everything he’d just seen, Gray sensed the pool was as deep as the Titans were tall.
Mac studied the space with a critical eye. “I wonder if this is the source for all of the oil plumbed throughout the city.”
“The true heart of Tartarus,” Bailey said.
Mac pointed across the pool to an apron on the far side, to a large bronze wheel set into the wall back there. “That could be the main cutoff valve for the city.”
Gray leaned closer, cupping his eyes against the glass. “Hunayn mentioned this was where he discovered a way to force Tartarus back to sleep. If that valve did shut off the city’s oil supply, the constructs would eventually consume whatever fuel had been pumped into them.”
“And then they’d shut down,” Mac said.
“Going back to sleep,” Maria added.
Mac nodded. “I saw something like that happen to the bronze crabs in Greenland. But not to the bronze bull. Though its bulk surely held a larger supply of fuel.”
“But how can we be sure