The drain led to a sub-basement channel.
It was a river of sludge. Cold, black, and smelling of ancient rot.
"Coat yourselves," Marcus ordered.
He scooped up a handful of the freezing muck. He slapped it onto his neck, his face, his arms. The cold shock made him gasp, but it dulled the burning pain of the acid.
"It will hide your heat signature," he explained. "To those things, we need to look like the walls."
Lucilla stood on the bank, her expensive suit ruined, her face pale.
"I can't," she whispered. "It's... excrement."
Marcus didn't argue. He grabbed her arm and shoved her into the channel.
She splashed into the waist-deep filth. She gagged, spitting black water.
"Dignity or death, Lucy," Marcus said cold. "Pick one."
He grabbed Narcissus's collar. The giant groaned but didn't wake. Marcus and Galen dragged him into the current.
They waded downstream.
The tunnel widened. They had entered the Cloaca Maxima—the Great Sewer of Rome.
It was a vaulted cathedral of brick, filled with the rushing refuse of a million people. The roar of the water echoed off the walls, drowning out the sounds of the palace above.
They moved in silence for ten minutes. The cold seeped into their bones. Narcissus shivered violently, his teeth chattering.
"Talk," Marcus said to Lucilla, keeping his voice low. "If I'm going to die in a sewer, I want to know why."
Lucilla wiped sludge from her cheek. She looked small now. The CEO mask was gone.
"They aren't invading," she said, her voice hollow. "The Board... they don't want subjects. They want the core."
"The core?"
"Rare earth elements," she said. "Gold. Lithium. The mantle is rich here. They plan to strip-mine the planet. But first, they have to fumigate."
"Fumigate," Marcus repeated. "Us."
"Yes. The Scourge units... they liquefy organics. They turn biomass into fuel. They will clean the surface until it is sterile rock. Then the mining drills land."
"They missed a spot," Marcus said. He looked at his battered team. A gladiator, a mad doctor, a fallen queen, and a time traveler.
"We're just debris to them," Lucilla said. "Ants in the carpet."
"Ants can kill a picnic," Marcus muttered.
SPLASH.
A sound behind them.
It wasn't the current. It was a heavy object hitting the water.
Marcus spun around. He raised his sword.
Nothing but black water.
"Did you hear that?" Galen whispered.
"Keep moving," Marcus said. "Faster."
They waded deeper. The water rose to their chests.
Suddenly, the water erupted.
A shape burst from the surface. Sleek. Eel-like. Chrome scales gleaming in the faint light filtering from a grate above.
A Swimmer.
It didn't have legs. It had thrusters.
It slammed into Galen.
The physician screamed as he was dragged under.
"Galen!" Marcus lunged.
He grabbed Galen's tunic. He pulled.
The machine was strong. It thrashed, its metal tail whipping the water into foam. A serrated jaw clamped onto Galen's leg.
Marcus stabbed at the machine, but the water slowed his blow. The sword glanced off the wet metal.
Galen's head went under. Bubbles rose.
Marcus was losing his grip.
Then, a hand—massive and cold—shot out of the water.
Narcissus.
The shock of the attack had woken him. The Iron Dog didn't think. He reacted.
He grabbed the machine by its optical sensor array.
He roared. A bubbling, underwater sound.
He slammed the machine's head against the brick wall of the sewer.
CRUNCH.
He did it again.
CRUNCH.
Glass shattered. Sparks fizzled in the water.
The machine convulsed and went limp.
Narcissus let go. He slumped back against the wall, chest heaving.
Galen surfaced, gasping for air, coughing up black water. His leg was bleeding, shredded by the metal teeth.
"Can you walk?" Marcus asked, hauling Galen up.
"Swim," Galen choked out. "I can swim."
"We're close," Marcus said. He could smell fresh air. "The outlet is ahead."
They scrambled forward, dragging their wounded.
The tunnel ended.
An iron grate barred the exit. Beyond it, the Tiber River flowed, silver in the moonlight.
Marcus grabbed the bars. He pulled.
Rusted solid.
"Help me!"
Lucilla grabbed a bar. Galen pushed.
It didn't budge.
Behind them, in the dark tunnel, a chorus of shrieks began.
Skree-clack. Skree-clack.
The swarm had found the entrance.
"They're coming!" Lucilla screamed.
"The powder!" Marcus yelled. "Galen, do you have any left?"
Galen fumbled in his pouch. He pulled out a small wax-sealed packet. "It's wet on the outside... maybe dry inside..."
"Pack the hinges!"
Galen jammed the wax ball into the rusted hinge of the gate. He stuck a short fuse into it.
"Fire!"
Marcus struck his flint against the stone wall. Sparks flew.
The fuse hissed.
"Dive!"
They submerged themselves in the filthy water.
WHUMP.
It wasn't a loud bang. The water muffled it. But the pressure wave hit them like a punch.
The hinge shattered. The heavy iron gate groaned and fell outward, splashing into the river.
The current caught them.
They tumbled out of the sewer mouth, gasping as they hit the open water of the Tiber.
The water here was cleaner, colder. It washed the sludge from their faces.
They drifted downstream, clinging to a large piece of driftwood.
Marcus looked back.
The sewer outlet was swarming. Dozens of Scourge units crowded the opening, their red eyes glowing in the dark. They screeched at the water, but they didn't follow. The river was too deep for the walkers.
Marcus looked up at the city.
Rome was burning.
But above the fire, something else was happening.
Beams of blue light were sweeping the city from the sky. Orbital lasers.
They moved in a grid pattern. Where they touched, buildings collapsed into dust. They were sanitizing the infection.
"They are erasing us," Lucilla whispered, clinging to the log.
Marcus watched the Palatine Hill crumble under a beam of light. The Throne Room, the servers, the luxury—gone in a flash of silent power.
He paddled hard, steering the log toward the muddy bank on the far side of the river, miles downstream.
They crawled onto the shore. They collapsed in the mud, shivering, wounded, and alive.
Galen rolled onto his back. He stared up at the orbital ships—stars that moved.
"Where now?" Galen asked softly. "The city is gone. The world is ending."
Marcus sat up. He wrung the water from his tunic.
He looked North. Toward the dark silhouette of the Apennine Mountains.
"They want to mine the earth," Marcus said.
He stood up. He offered a hand to Narcissus.
"The Etruscans dug deep mines in those hills," Marcus said. "Miles of tunnels. Dark. Cold. Defensible."
He looked at the orbital lights one last time.
"If they want the rock," Marcus rasped, "let's show them what lives inside it."