Instinctively, Kiyomi jabbed out a hand, latched on to the turtle’s shell and flattened herself against its back. The shark’s teeth clamped down hard on seawater and it wheeled away, returning to its master, baffled as to how its meal had vanished.
At the same time, Kenny took one look at the savage teeth closing in and hurled himself upwards, out of the chasm, and into the trap. The waiting shark-riders pounced on him, spears at the ready.
Kusanagi, the Sword of Heaven, flashed into Kenny’s hand and, with one stroke, spearheads tumbled towards the seabed. The pursuing eels scattered before attacking from three different directions. The sword moved to protect its master, slashing first downwards, then flipping Kenny upside down to deliver a reverse sweep before slicing horizontally. Swirls of blood stained the water pink and chunks of eel floated downwards.
The sharks and their riders hesitated, while the giant leatherback cruised past. Kenny glimpsed the yellow blur of a scuba tank on its back and kicked off, chasing after the turtle. It was surprisingly fast and Kenny, worried he wouldn’t catch up, wondered if he could summon a current of water to push him along. Kusanagi bucked in his hands, spinning him round to take off the nose and lower jaw of a mako that had closed in.
With a flick of its enormous flippers, the leatherback changed direction, heading for the ruins of the city. With Kiyomi holding on, Kenny followed. Behind him, at a safe distance, came the sharks and their riders.
The turtle skimmed the surface of the top terraces and dropped sharply over the edge, gliding towards a narrow gap in the rocks. A stone slab rested on top of two monolithic blocks, forming a Stonehenge-like rectangular arch. The space was tight and Kenny, swimming as fast as he could, wondered what the great sea reptile was doing. It was easily three metres long from head to tail, with flippers of the same length; there was no way it could fit through the opening.
Looking up past the turtle’s head, he saw Kiyomi release her grip as the turtle rolled on to its side and soared towards the passage. Kusanagi jerked in Kenny’s hand, deflecting another spear, while the pursuing shark pack spread out to encircle him. He beckoned for Kiyomi to join him, but she was staring at the leatherback heading for the rocks.
The shadow of the arch fell across the turtle and it ducked its head, folded its flippers like a pair of wings and sailed into the gap, where it flickered and vanished.
Kiyomi looked from the archway to Kenny and to the sharks around him. Silvery shapes in the distance signalled that reinforcements were on the way. She furiously gesticulated for Kenny to follow and struck out for the archway. Seeing this, two shark-riders broke formation to stop her.
Kenny had seen enough. Screwing his eyes shut, he concentrated, imagining an underwater tsunami rolling over the seabed. A roaring sound filled his ears and the nearest sharks were flipped tail over head, then slammed into the sides of the ruins. The surging current struck Kenny like a wall, flinging him towards the rocks.
Swimming hard, Kiyomi glanced over her shoulder; her eyes widened and Kenny ploughed into her, grabbing her by the scuba harness and holding on. The archway loomed larger and Kenny barely had time to direct the wave through the narrow entry. He twisted round, shielding Kiyomi with his body, and the surging tide carried them both through the gap.
Kenny had a moment of weightlessness before crashing down to land on something hard. ‘OWW!’ he yelled and the regulator popped out of his mouth. In a panic, he scrabbled for his alternate air source, then stopped. He could breathe.
Kiyomi was sprawled at his feet in the damp sand. Kenny struggled to sit up, but his whole body felt leaden. He released the catch on his weight belt and shrugged out of the scuba-tank harness, rising to his knees. Kiyomi had done the same and was staring in rapt wonder at the scene around them.
They were on the seabed, but no longer in the water. A quicksilver membrane billowed above, enclosing them in a spacious bubble of air. Outside, beyond the pulsing walls, sea creatures were watching them as if they were interesting zoo exhibits. Fish of all shapes and sizes pressed close to the glistening surface and peered in: giant groupers, majestic rays, globular puffers, domed jellyfish, bluefin tuna, fluttering sea horses.
‘Kenny, is this your doing?’ Kiyomi whispered, removing her face mask.
‘No. No way. At least . . . I don’t think so,’ Kenny answered, also pushing up his mask.
‘Then who –?’
A bassoon-style drone reverberated through the air pocket, abruptly changing pitch to an echoing squeal. Kenny glanced upwards to see the source of the noise, and gaped at the immense bulk of a whale passing overhead like a jumbo jet.
‘Is this some kind of welcoming party?’ he wondered aloud.
‘You wish,’ Kiyomi muttered. ‘More like a buffet line and we’re on the menu.’
The bubble wall quivered behind Kenny and crept inwards.
‘Uh-oh,’ he said. ‘Is this thing shrinking? Are we using up the air?’
‘No,’ Kiyomi said, kneeling to examine the perimeter. ‘Carbon dioxide would replace the oxygen; it wouldn’t shrink. It’s changing shape. See for yourself. This end is contracting, but the opposite side, over there, is expanding. It’s elongating.’
As Kenny watched, the bubble stretched out a wide, tunnel-sized, amoeboid limb. The shrinking end of the air pocket was almost by his feet now. He kicked off his flippers and started walking along the extended arm.
‘What are you doing?’ Kiyomi asked.
‘This bubble is moving,’ Kenny said. ‘If we don’t move with it, we’ll be left on the bottom of the sea, surrounded by all those hungry mouths. If we go with it, at least we stay alive a bit longer.’
‘But what about our gear?’ Kiyomi said, pointing at their scuba tanks on the sand. ‘We can’t just leave our stuff behind. How are we going to get back up to the surface?’
‘This thing isn’t going to wait for us.’ As if to emphasise the point, the bubble wall slid over Kenny’s flipper, which was snatched up and carried away by a red sea bream.
Kiyomi stood her ground, fuming, until the membrane wall touched the back of her head and she felt the sting of icy-cold water against her scalp. ‘OK, you win!’ she yelled, slipping out of her scuba equipment and scurrying beside Kenny. She clasped his hand and together they walked along the seabed, directed by the air tunnel that rolled ahead of them.
Before long, the sand underfoot changed to a finer pinkish material, which formed a wide strip.
‘Is this a road?’ Kenny said.
Kiyomi nodded. ‘Ground-up coral. Looks like it goes through that rock wall.’
The bubble bounced up against a cave-like entrance in a low cliff, shuddered and squeezed itself inside. Kenny prepared to call up a ball of light, but there was no need; the inside of the tunnel was lined with bioluminescent plankton and glowed a starry blue. A reddish gleam marked the end of the passage and, when they reached it, the rock walls opened out on to a scene that left both Kiyomi and Kenny open-mouthed.
Towering
