The tunnel took a long, shallow bend. Ahead, Margo could see Snow and D’Agosta already moving into a large vaulted space at the end of the tunnel.
Beside her, she could hear Smithback’s breathing turn choppy. Her eyes drifted toward the tunnel floor. Around her lay the torn and bloodied bodies of perhaps a dozen Wrinklers. She caught a glimpse of a dirty hood, burned away to expose skin seamed and veined to an extraordinary thickness.
“Striking,” Pendergast murmured at her side. “The reptilian traits are unmistakable, yet the human attributes remain dominant. An early way station, so to speak, on the way to the full-blown Mbwun-hood. Odd, though, how the metamorphosis is so much greater in certain specimens than in others. No doubt due to Kawakita’s continual refinements and experimentations. Shame there’s no time for further study.”
The echoes of their footfalls grew broader as they moved into the large space at the end of the tunnel. There were several more still forms lying scattered in the shallow water.
“This was our rally point,” Snow said as he sorted quickly through the rows of equipment lining one side of the vaulted space. Margo could hear the sharp edge of nervousness in his voice. “There’s more than enough scuba equipment here to get us out, but no suits. Look, we’ve got to move quickly. If we’re still here when those charges blow, this whole place is going to come down on top of us.”
Pendergast handed her a set of tanks. “Dr. Green, we have you to thank for our escape,” he said. “You were right about the vitamin D. And you were able to contain the creatures within the Pavilion until the explosions blocked their escape. I promise you’ll be welcome on any further excursions we may make.”
Margo nodded as she snugged her feet into a pair of flippers. “Thanks, but once was enough.”
The FBI agent turned toward Snow. “What’s the exit strategy?”
“We came in through the Sewage Treatment Plant on the Hudson,” Snow replied, shouldering his air tank and strapping on a headlamp. “But there’s no way to return through the plant. We were to leave via the north branch of the West Side Lateral, to the One Hundred Twenty-fifth Street Canal.”
“Can you get us there?” Pendergast asked, quickly passing air tanks to Smithback and helping to fit them.
“I think so,” Snow panted, pulling masks out of the equipment pile. “I had a good long look at the Commander’s maps. We retrace our route as far as the first flow riser. If we ascend the riser instead of descend, we should reach the access spillway leading out into the Lateral. But it’s a long swim, and we’ll have to be extremely careful. There are sluice gates and evacuation shunts. Get lost down those, and…” His voice petered off.
“Understood,” Pendergast said, shrugging into a set of air tanks. “Mr. Smithback, Dr. Green, ever used scuba gear before?”
“Took a few lessons in college,” Smithback said, accepting the proffered mask.
“Skin-dived in the Bahamas,” Margo said.
“The principle’s the same,” Pendergast said to her. “We’ll adjust your regulator. Just breathe normally, stay calm, and you’ll do fine.”
“Hurry!” Snow said, real urgency in his voice now. He began to jog toward the far end of the vaulted space, Smithback and Pendergast close behind him. Margo forced herself to follow, tightening her tank belt as she ran.
Suddenly, she was brought up short by Pendergast, who had stopped and was looking over his shoulder.
“Vincent?” he asked.
Margo turned. D’Agosta was standing behind them in the center of the vault, the air tanks and mask still in a pile by his feet.
“You go on ahead,” he said.
Pendergast looked inquiringly at him.
“Can’t swim,” D’Agosta explained simply.
Margo heard Snow curse fervently under his breath. For a moment, nobody moved. Then Smithback stepped back toward the Lieutenant.
“I’ll help you out,” he said. “You can follow me.”
“I told you, I grew up in Queens, I don’t know how to swim,” D’Agosta snapped. “I’ll sink like a damn stone.”
“Not with all that blubber, you won’t,” Smithback said, snatching a tank off the ground and placing it on D’Agosta’s back. “Just hold on to me. I’ll swim for both of us, if need be. You kept your head above water back in the subbasement, remember? Just do what I do and you’ll be okay.” He thrust a mask into D’Agosta’s hands, then pushed him ahead toward the group.
At the far end of the chamber, an underground river ran off into darkness. Margo watched as first Snow, then Pendergast, adjusted their masks and eased themselves into the dark liquid. Pulling her mask down over her eyes and placing the regulator in her mouth, she slid in after them. The air of the tanks was a welcome relief after the foul atmosphere of the tunnel. Behind her, she could hear a loud splashing as D’Agosta half swam, half floundered through the viscous, lukewarm liquid, Smithback urging him on.
Margo swam as quickly as she could through the tunnel, following the flickering light of Snow’s headlamp, expecting at any moment to feel the massive concussion of the SEAL charges bring the ancient stone ceiling down behind them. Ahead, Pendergast and Snow had stopped, and she pulled up beside them.
“We go down here,” Snow said, popping the regulator from his mouth and pointing downward. “Be careful not to scratch yourself, and for God’s sake don’t swallow anything. There’s an old iron pipe at the base of the tunnel here that leads—”
At that moment they felt, rather than heard, a vibration begin over their heads: a low, rhythmic rumbling that grew to a terrible intensity.
“What’s that?” Smithback gasped, coming up with D’Agosta. “The charges?”
“No,” Pendergast whispered. “Listen: it’s one continuous stream of sound. It must be the dumping of the Reservoir. Prematurely.”
They hung there in the foul liquid, mesmerized despite the danger by the long rolling sound of millions of gallons of water roaring down the ancient network of pipes that crossed and recrossed above their heads, heading directly for them.
“Thirty seconds until the rest of the charges go,” Pendergast said quietly, checking his watch.
Margo waited, trying to steady her breathing. She knew that if the charges failed, they’d be dead within minutes.
The tunnel began to vibrate violently, the surface of the water jiggling and dancing. Small pieces of masonry and cement began to rain down into the water around them. Snow tightened his mask and took a last look around, then sank beneath the surface. Smithback followed, pushing the protesting D’Agosta before him. Pendergast motioned Margo to go next. She sank into the darkness, trying to follow the faint light of Snow’s headlamp as it descended into a narrow, rust-coated pipe. She could see the ungainly thrashing of D’Agosta subside into more regular movements as he became used to breathing tank air.
The tunnel leveled out, then snaked around two bends. Margo took a quick look behind to reassure herself that Pendergast was following. In the dim light of the swirling orange effluent, she could see the FBI agent motion her forward.
Now, she could see the group pausing at a junction ahead of her. The ancient iron pipe ended and a gleaming steel tube continued onward. Beneath her feet, at the point where the two tunnels met, Margo could see a narrow tube leading downward. Snow gestured ahead, then pointed upward with his finger, indicating that the vent riser to the West Side Lateral was directly ahead.
Suddenly, there was a roar from behind them: an ominous, deep rolling sound, horribly magnified in the tight water-filled space. Then a sharp concussion sounded, and another, following one upon the other in rapid succession. Beneath the wildly flickering beam of his headlamp, Margo could see Snow’s eyes widen. The final set of charges had gone off barely in time, crushing the spillways from the Devil’s Attic, sealing it forever.