The Chicago Deep Tunnel system, officially called the Tunnel and Reservoir Plan (TARP), was an engineering wonder built to hold billions of gallons of sewage and stormwater runoff. It was a concrete cathedral, thirty feet wide and three hundred feet below the city.
It was never intended for anyone to inhabit.
Jax hit the water like a stone. The current was freezing, a mix of ice melt and industrial runoff that tasted like oil. He tumbled in the darkness, his heavy pack dragging him down. He couldn't see the bottom, but he felt the pressure pop his ears.
A metal hand grabbed his collar.
Silas pulled Jax out of the swirling water and onto a narrow maintenance ledge. Jax collapsed, coughing up black water and shaking uncontrollably.
"Status," Silas demanded, pulling Isobel up beside them.
"Wet," Jax said through chattering teeth. "Freezing. Battery... dead."
He tried to generate a spark to warm himself. A weak flicker of blue light appeared on his thumb but disappeared immediately. The dampeners in the Greyhawk weapons had really messed with his body. He felt like a phone almost out of battery in a freezer.
Isobel stood up without shivering. The water dripping from her dress froze into delicate, black icicles before hitting the concrete.
"We are deep," she whispered. Her voice echoed eerily in the vast tunnel, bouncing off the curved walls. "The silence here is thick."
Silas sat down heavily, his left leg stiff and unmovable. He pulled a glow-stick from his belt and cracked it open. The green chemical light brightened the tunnel, which extended endlessly in both directions, a perfect, man-made tube filled with rushing dark water.
"My knee actuator is stuck," Silas said with a grunt. He rolled up his pant leg to reveal a metal joint that wasn't bent but rather grey and lifeless. The Greyhawk's weapon had changed the living tungsten back into inactive lead. "I can't run."
"So we walk," Jax replied, wringing out his coat. "Where are we? The Mainstream Pumping Station?"
"Lower," Silas said, pulling a blowtorch from his pack. He didn't light it; the igniter clicked uselessly. "Wet flint. Damn it."
"Let me," Jax offered, reaching for the torch. He focused on trying to push a tiny volt into the striker.
Nothing. No spark.
"I'm empty, Silas," Jax said, his voice sounding hollow. "The resonance bomb... plus the cold... I'm out."
Silas looked at him, then put the torch away. He pulled out a physical flare, tore off the cap, and shoved it into his knee joint. The magnesium flared white-hot. Silas didn't react as the heat melted the lead, allowing him to force the joint back into a functional, though ugly, shape.
"We keep moving," Silas said, standing up on the damaged leg. "The Greyhawks will send out tracker drones. We need to find the breach point before they trace our heat."
"Which way?" Jax asked.
Isobel pointed into the darkness, against the current of the water.
"Toward the thumping," she said.
Jax listened. He heard the water and the distant rumble of the city above. But beneath it, he heard—or felt—a slow, steady vibration. Thump... Thump...
"The Heart," Isobel said. "It's waking up."
They walked for an hour. The air warmed up, becoming humid and smelling of ozone and decay. The concrete walls started to change. The smooth engineering of the TARP system gave way to patches of glowing, bioluminescent mold that pulsed in tune with the heartbeat Isobel sensed.
"Don't touch the walls," Silas warned, the flare casting long, flickering shadows. "That's Alchemical residue. Runoff from the surface war. It has mutated the plants."
"Moss can't have teeth," Jax nervously said, eyeing a patch that seemed to be watching him.
"It does now."
They rounded a bend and stopped. The maintenance ledge ended. Ahead, the tunnel had collapsed—or rather, it had been gnawed through. A large hole in the tunnel wall opened into a rough-hewn cavern that hadn't been made by machines.
"Here," Isobel said. "The Deep Tunnels intersect with the natural caverns."
"Wait," Jax hissed, grabbing Silas's arm. "Cut the light."
Silas put out the flare.
Total darkness rushed in, broken only by the faint, sickly green glow of the mutated moss.
"I hear claws," Jax whispered.
Skittering sounds filled the air—hundreds of tiny, sharp impacts on the concrete. It came from the hole in the wall.
Two red eyes appeared in the darkness. Then two more. And then a hundred.
They weren't rats. They were the size of corgis, hairless, with skin that looked like clear plastic. Jax could see their organs pulsing with trapped, erratic magic through their ribs.
Spark-Eaters.
"Scavengers," Silas whispered, shifting his weight to his good leg. "They feed on magical runoff. They're drawn to energy."
"Great," Jax replied. "I'm a battery."
"You're a dead battery," Silas corrected. "They're smelling Isobel."
The lead rat hissed, a sound like steam escaping a pipe, and lunged.
"Move!" Silas shouted.
He swung his heavy pack, catching the rat in midair and smashing it against the wall. It burst in a spray of acidic green goo.
The swarm surged forward, a carpet of teeth and hunger.
"Get behind me!" Silas commanded. He planted his feet, his copper-wired suit starting to heat up as he tapped into his internal reserves. He couldn't change the whole swarm, but he could create a barrier.
He slammed his hands onto the concrete ledge.
RUMBLE.
The stone rippled, rising to form a waist-high wall. The rats scrambled over it quickly, their claws skittering on the smooth stone.
"Too many!" Jax yelled, kicking a rat that tried to bite his boot. He stomped on it, hearing a sickening crunch. "Isobel! Do the spooky thing! Tell them to stop!"
"They aren't dead, Jax!" Isobel shouted, backing away. "They're alive! I can't control hunger!"
A rat jumped onto Silas's back, biting into the copper cabling of his suit. Silas grunted, reaching back to rip it off, but three more sank their teeth into his arm. They gnawed through the metal, seeking the energy inside.
"They're eating the suit!" Silas yelled. "They sense the charge!"
Jax looked around, feeling helpless. He had no spark, no weapon, and he was trapped on a ledge over rushing sewage.
Then he spotted it.
Running along the ceiling of the tunnel, covered in grime and moss, was a thick black cable. A 12,000-volt municipal power line feeding the pumping stations.
It was frayed. A small section of copper was exposed, sparking rhythmically in the damp air.
Jax glanced at the rats swarming Silas and then at the cable. It was ten feet up.
"Hey! Vermin!" Jax shouted.
He whistled.
The swarm paused. The lead rats turned their red eyes toward him.
"You want juice?" Jax yelled. "Open bar!"
Jax didn't try to spark. He used his kinetic training—parkour. He jumped onto the barricade Silas had made, sprang off the tunnel wall, and grabbed the frayed cable with both hands.
"Jax, no!" Silas shouted. "You aren't insulated!"
Jax didn't absorb the power. He didn't try to control it. He simply became the wire.
He swung his body, using his weight to snap the rusted brackets holding the cable to the ceiling.
SNAP.
Gravity took over. Jax fell, bringing the live 12,000-volt line down with him.
He landed in the center of the rat swarm, jamming the live end of the cable into the wet puddle they stood in.
ZZAAP.
The tunnel flashed blinding white. The water on the ledge instantly vaporized into steam.
Jax was hurled backward by the shockwave, sliding dangerously close to the edge of the deep water.
Silence returned to the tunnel, replaced only by the smell of ozone and burnt fur.
Jax lay on his back, smoke curling from his sleeves. His hair stood straight up.
"Ow," Jax groaned.
Silas limped over, kicking aside the charred bodies of the rats. He looked down at Jax.
"That was reckless," Silas said. "Inefficient. And... effective."
Jax sat up, grinning weakly. His eyes were glowing a faint, steady blue again.
"Jumpstarted," Jax coughed. "I think I got about 10% back."
Isobel walked to the hole in the wall. The rats had vanished, scattered or fried.
"The way is clear," she said, looking back at them with a pale face in the gloom. "But we aren't alone down here. The Greyhawks have entered the system."
"How do you know?" Jax asked, standing up unsteadily.
"Because," Isobel said, pointing to the water. "The current just stopped."
Jax looked. The black water in the main tunnel was still. It wasn't flowing anymore. It was freezing.
"They dropped a cryo-bomb upstream," Silas realized. "They are freezing the tunnel to walk on the ice. They're catching up."
"Then we go deep," Jax said, turning toward the rough-hewn hole. "Into the rabbit hole."
They stepped through the breach, leaving the concrete world of man behind as they descended into the ancient, living earth beneath Chicago.