Claustrophobia isn't the fear of enclosed spaces. It's the fear of not having enough room for your lungs to expand when you need to scream.

  The interior of the Guanabara-South Zone Pipeline was a concrete and steel tube four meters in diameter. It was submerged, but not filled with water. It was filled with a thick, oily black sludge that our amphibious truck cut through with difficulty, like a dull knife slicing through cold molasses.

  "We're thirty meters deep," Valéria informed, her voice tense, eyes fixed on the dashboard gauges. "External pressure is denting the bodywork. If we spring a leak, the truck fills with oil in five seconds and we drown in magical petroleum."

  "Optimistic as always," I commented, observing the black liquid through the reinforced window.

  Outside, the fog lights could barely pierce the darkness. The "oil" wasn't inert. It moved in slow, almost hypnotic currents. Small pieces of bone and debris floated suspended in the goo.

  "The smell is getting in," Gristle covered her snout with a wet cloth. "Smells like a whale graveyard."

  "Because that's exactly what it is," I analyzed the portable spectrometer. "This isn't ordinary fossilized petroleum. This is Necrotic Hemoglobin. Blood of ancient sea monsters, mixed with industrial waste and black magic. The Church of High Tide is literally pumping the rot from the bottom of the bay to feed the city."

  Suddenly, the truck gave a violent jolt. The engine sputtered.

  The dashboard lights flickered.

  "What was that?" Luna asked, gripping the armrest.

  "Turbulence?" suggested Valéria.

  "There is no turbulence in fluids of this viscosity," I replied, unbuckling my seatbelt. "Something hit us."

  I turned off the internal cabin lights to see better outside.

  I pressed my face to the glass.

  At first, it looked like just a smudge in the oil. A darker shadow within the dark.

  But then, the shadow smiled.

  A face formed in the tar, pressed against the glass on the outside. It had no eyes, just empty holes and a torn mouth full of teeth made of broken glass and sharp trash.

  "Petroleum Siren," I whispered.

  She didn't sing. She screamed.

  The sound was muffled by the liquid and the glass, but the vibration made the truck chassis groan.

  Black hands, long and shapeless, emerged from the liquid and grabbed the windshield wipers, trying to rip them off.

  "There's more of them!" shouted Gristle, looking through the rear hatch. "They're trying to get in through the exhaust!"

  The truck began to slow down. The slime around us was getting denser, hardening. The Sirens were manipulating the fluid's viscosity to trap us in place, like flies in amber.

  "Valéria, accelerate!" I shouted.

  "I'm flooring it! The propellers are jammed! They got into the turbines!"

  The truck stopped completely.

  The silence of the dead engine was terrifying.

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  Outside, dozens of black shapes slid over the vehicle, looking for a crack. We heard the sound of metal being scratched and corroded. Sssssss...

  "They're acidic," I realized, seeing a rust spot spread quickly on the side door. "They're going to dissolve the armor and get in."

  "Shooting won't work," Gristle brandished her cleaver, frustrated. "If I cut them, the blade melts. And they're liquid, they'll just reform."

  "Arthur!" Luna looked at me, terrified. "Fire?"

  "If we light a match inside this tube full of volatile gases, the explosion will open a crater in Rio de Janeiro and send us to the moon in little pieces. Fire is forbidden."

  I needed to think fast.

  Elementary biology. They are made of pollution and mana, held together by magical surface tension.

  They are a non-newtonian fluid: hard on impact, but liquid with constant vibration.

  "Luna!" I looked at her. "You are the weapon. Sound travels four times faster in liquids than in air. And it travels even better in dense solids."

  "What do I do? Scream?"

  "No. You need to resonate." I pointed to the truck roof. "Put the baton against the metalwork. The truck will be your speaker box. I need you to sing a low, dissonant note. A frequency that breaks the surface tension of the oil."

  "It's going to make my teeth fall out," she complained, but positioned the baton against the roof metal.

  "Valéria!" I turned to the driver. "Prep the ignition. When the oil 'liquefies,' you'll have three seconds to start the engine before they solidify again."

  "Understood."

  "Gristle, protect the seals. If any of them get in, use the chemical powder extinguisher. It's the only thing that dries them out."

  "And you, Doctor?"

  My eyes glowed purple. The Parasite extended mana tendrils through my hands.

  "I'm going to be the drain."

  I placed my hands on the cold metal door.

  The Parasite crossed the physical barrier with its aura. I felt the Sirens on the other side. They were cold, toxic, and full of hate. They were the soul of pollution.

  "Luna, now!"

  Luna activated the baton.

  HUUUUUUMMMMMM.

  The entire truck vibrated. I felt my bones rattle. The sound propagated through the metal and out into the oil outside.

  The reaction was immediate.

  The Sirens, which were hardened and clinging to the vehicle, began to lose shape. Their bodies "melted," unable to maintain physical cohesion under the sonic vibration.

  The faces melted. The claws turned into puddles.

  "They're turning into soup!" shouted Gristle, watching through the rear glass.

  At the same time, I activated my Mana Drain.

  I sucked the magical energy animating the tar.

  It tasted horrible—like old batteries and rotten fish—but it worked.

  Without the magic to hold them and with the sound destroying their physics, the Sirens dissolved into ordinary inert oil.

  The solid "blockage" around the propellers undid itself.

  "NOW, VALéRIA!"

  Valéria turned the key. The engine coughed, choked, and roared.

  The propellers spun free in the liquefied slime.

  The truck shot forward, running over the remains of the dissolved Sirens.

  We sped through the dark tube, leaving the danger zone behind.

  "Keep the vibration going for another kilometer!" I ordered, tasting the metallic toxic mana in my mouth. "Don't let them reform!"

  We traveled for another ten minutes in absolute tension.

  Finally, I saw a light at the end of the tunnel. It wasn't sunlight. It was an artificial, bluish, sterile light.

  The pipeline was ending.

  We reached a giant metal grate. Behind it, a massive settling pool.

  Valéria braked the truck before we hit the grate.

  "We're here. South Zone Treatment Station."

  We turned off the engine. Silence returned, but now without the oppressive weight of the Sirens.

  I looked at Luna. Her nose was bleeding a little from the sonic effort.

  "Good job, boombox."

  "Don't ask me to do that again," she wiped the blood. "I feel like my brain turned into a milkshake."

  Gristle looked out the window.

  "Doctor... look where we are."

  I looked through the grate.

  We were inside a colossal artificial cavern, carved into the base of Corcovado Mountain.

  And inside, floating in the settling pool, wasn't just oil.

  There were Eggs.

  Thousands of translucent eggs, the size of cars, pulsating with blue light. Inside them, silhouettes of gestating sea monsters grew, fed by the pipeline blood.

  And above the pool, suspended by chains, was the hull of a gigantic ship under construction.

  The Ark.

  It wasn't made of wood. It was made of polished Kaiju bones.

  "They aren't building an escape ship," I whispered, horrified. "They're building a biological aircraft carrier. They're going to invade the mainland using the sea."

  "How do we get in?" asked Valéria.

  I pointed to a ventilation duct above the grate.

  "We're going to have to leave the truck here. From here on out, we're on foot. And silent.

  "We are in the enemy's nursery. And I think we just found out who the mother is."

  We got out of the truck, entering the oily water up to our waists, and swam to the grate.

  Valéria used the underwater torch to cut a passage.

  We entered the High Tide Monster Factory.

  The smell of incense and formaldehyde was strong. Distant chants echoed off the stone walls.

  The true face of Rio de Janeiro's religion was about to be revealed. And it had scales.