‘ Schiuma, you mean,’ Jack said. ‘That’s exactly what Massimo called it.’
Costas put a foot into the torrent, holding tight with both hands to the rope. His foot created a wide wake, with foam streaming off to either side. He lifted it out, and what seemed to have been brown foam but was actually a stringy mass came out with it. He thrust his foot back in, shaking it violently. ‘Jack, that was just about the worst thing that has ever happened to me,’ he said, panting. ‘Why this? We could be in the crystal-clear waters off Sicily. Lying by a pool, having a long-overdue holiday. But no, we go diving in a sewer.’
‘Fascinating.’ Jack was squatting on the step behind Costas, peering at a pile of washed-up debris just above the torrent. Costas twisted around, his foot still in the water. ‘Have you found it? Can we go now?’
Jack pushed aside some rodent bones, and held up a slimy chunk of pottery. ‘Roman amphora sherd. Dressel 2 to 4, unless I’m mistaken. The same type we found on the shipwreck, and in Herculaneum. The wine Claudius would have drunk. This stuff got everywhere.’ He put his other hand deep into the sludge, and grunted. ‘There’s more.’
‘Leave it, Jack.’
Jack paused, then pulled out his arm and stood up. ‘Okay. Just being an archaeologist.’
‘Save it for this secret chamber. If we ever get there.’ Costas took the coil of rope from his shoulder. He clipped one end to the piton holding the fluorescent line, and the other end to his harness. ‘I think we can sacrifice one rope here, for safety,’ he said. ‘I refuse to end my days in a torrent of shit. Clip on behind me.’ He turned back and stepped down until the liquid was nearly chest-high, flecking his visor with foam. ‘I’m on the ledge,’ he said. ‘Moving ahead now.’ Jack followed him, feeling the pressure of the water push hard against his legs and then his waist. They began to progress along, painfully slowly, a few inches at a time. The water felt heavy, cloying, and Jack could see iridescent streams of oily matter on the surface, then shifting blotches of brown and grey, a camouflage colour. He tried to focus on the walls, the ceiling, on stonework which had been built well before the Roman Empire, when the Velabrum was first covered over. He arched his head back, and realized the tunnel had taken a slight curve to the right. The steps they had come down from the spiral staircase were now out of view. He turned forward and slogged on, beginning to pant hard with the exertion. He looked down to check his carabiner on the line and then looked up. Costas had vanished. He blinked hard, and wiped his mask. He was still gone. For a horrified moment he thought Costas must have fallen in, and he braced himself for the whip of the rope as he was swept past. Then he saw a dull glow coming from the wall about five metres in front of him, and a yellow helmet appeared.
‘This is the side tunnel,’ Costas said. ‘I’ve clipped the other end of the rope to a piton inside.’ Jack heaved himself against the current for the final few steps, then Costas reached out and hauled him in. Both men sat for a moment slumped against the side of the tunnel, panting. Jack sucked at the hydrating energy drink stored inside his suit, sluicing it round his mouth to get rid of the unpleasant taste. He looked around. They were in a smaller tunnel, but it was still a good three metres high and three metres across, with an arched barrel-vaulted roof and a flat bottom, a channel filled with water flowing down the centre. The flow was exiting into the Cloaca Maxima, and the water was clear.
‘Time for a final reality check,’ Costas said, peering at his wrist gauge. ‘This must be it. The Velabrum. It’s orientated straight into the Palatine Hill, and I can see Massimo’s line running ahead along the right side as far as I can make out, to wherever they stopped.’
Jack put his hand on the side of the tunnel. ‘This is an impressive piece of engineering,’ he said. ‘The Cloaca Maxima has masonry and brickwork from lots of periods, from when it was first covered over in the sixth century BC. But this is different, a single-period construction. Regular, rectilinear blocks of stone at the entrance. If I didn’t know better, I’d say we were walking into one of the great aqueduct channels made by the emperors.’
Costas looked at Jack through his visor. ‘About this Lupercale place, Jack. The cave of Romulus and Remus. I didn’t have a clue what you were on about.’
‘Sorry to spring that on you. Massimo and I did talk about it at that conference where we met him in London, shortly after the discovery of the cave under the House of Augustus was announced. I told him I’d love to come and take a look, to join his urban speleology group. When I realized yesterday we were coming to Rome, it was the perfect pretext. Once I guessed that Pliny must have hidden the scroll under the Palatine Shrine of Vesta, right next door to the House of Augustus, I also realized it was the site where the Lupercale was found. At the moment we just can’t risk bringing anyone else in on this quest. I hate keeping Massimo in the dark, but maybe he’ll forgive us once we tell him the role he played.’
Costas grunted, got up and started forward again, the rivulet of clear water from the darkness ahead rising over his ankles.
‘I hate to say this, Costas, but you’re trailing something.’ Costas turned round, stared, and made a strangulated noise. A mess of stringy brown tendrils extended back from his left foot towards the Cloaca, and caught in their midst was a writhing form with a long black tail. Costas shook his foot frantically, and the whole mass slithered off out of sight into the drain. ‘Never again, Jack,’ he muttered. ‘I swear to God, you’re never doing this to me again.’
‘I promise I’ll make it up to you. Next dive will be pure heaven.’
‘We’ve got to get out of this version of hell first.’ Costas resumed his slog up the tunnel, and Jack followed close behind. He still felt connected to the world outside, only a quick abseil along the rope back to the base of the spiral staircase, but with every step now the underworld seemed to be closing in on him, with darkness ahead and behind and only the immediate walls of the tunnel visible in their headlamps. He forced himself to concentrate, to push aside the claustrophobia, counting his steps, estimating how close they were getting to the foot of the Palatine Hill. After thirty paces he sensed that the angle had changed, that they were going down. The walls appeared buckled, fractured. The fluorescent line ended abruptly at a piton in front of a dark pool, and he could see where the ceiling sloped down into the water about five metres ahead.
‘This isn’t natural,’ Costas murmured. ‘I mean, the tunnel wasn’t designed this way. It looks like damage from seismic activity, like some of those fracture lines at Herculaneum.’
‘They get earthquakes here too,’ Jack said.
‘A pretty big one, but some years ago, centuries probably. And this might be a dead end for us, though there’s still plenty of flow getting through.’
‘Time for a swim,’ Jack said.
Costas sloshed into the pool, then disappeared in a mass of bubbles. Jack followed close behind, dropping to his knees and flopping forward, hearing the air in his suit expel as his computerized system automatically adjusted to neutral buoyancy. The water was extraordinarily clear, cleansing, like the underground cenote they had dived through in the Yucatan, and even here Jack felt the exhilaration he always felt as he went underwater, the excitement of the unknown. He reached back and slipped his fins down from where they had been tucked up behind his calves, and powered forward after Costas. His depth gauge showed three metres, then six. The earthquake had created a sump in the tunnel, and they were coming back up again. He saw in front of him that Costas had surfaced, and that the floor of the tunnel rose up to less than a metre depth. He swam up as far as he could, pulled his fins up again and rose out of the water beside Costas, who was staring ahead down the tunnel.