Chase warily examined the pool, watching the ripples subside. “Same way the traps still work-those bastards outside.”

“Nina, it’s okay, it’s okay,” said Kari, trying to comfort her. “Mr. Chase, can you see anything else?”

Keeping his feet a cautious distance from the edge, Chase leaned out over the pool, shining the light up at the ceiling. “There’s something up here, over the beam, but I can’t see what it is. Like a recess in the wall.”

“Can you reach it?”

“No, it’s too high… Oh, I get it. To get a proper look, you’ve got to cross the pool to where the dagger is.”

Kari let out a long breath. “Okay. Then I suppose I’m going to have to go and get it.”

“You?” Nina objected. “But you’re hurt!”

“You sure?” Chase asked. “I mean, it’s a narrow beam, but I could probably make it…”

In reply, Kari effortlessly cartwheeled into a handstand, holding herself on just her uninjured right arm before flipping back elegantly onto her feet.

“Okay,” said Chase, nodding. “So you go and get the dagger…”

Nina looked at the pool, worried. “Kari, are you sure? If one of those things sees you…”

“We don’t have a choice,” Kari said, going to the end of the beam. “How much time have we got?”

“Forty-one minutes,” Chase told her.

“Then I’d better hurry.” She stepped down carefully from the platform onto the wooden beam. It creaked, flexing slightly. Chase held up the flashlight to illuminate her path. Composing herself, Kari slowly stretched out her arms for balance, holding in a little moan as pain jabbed through her injured arm. “Okay. Here I go.”

She took a first step. The beam creaked again, more loudly. To everyone’s alarm it also wobbled, the supporting poles swaying in the water, causing ripples.

Other ripples appeared in the pool, near the aqueduct at the downstream end of the chamber. The sinister eyes of a caiman broke the surface, the rest of its long body barely visible beneath the algae-filled water. “Kari…” Nina warned.

“I see it,” she said, returning her full attention to the beam as she advanced, step by careful step. She was at a point halfway between two of the support poles, and the beam was sagging alarmingly, only a couple of inches above the water.

The caiman moved, its tail undulating sinuously from side to side as it drifted towards her.

Kari ignored it, concentrating solely on keeping her balance. The next support pole was now almost beneath her. That stopped the beam from sagging-but the whole affair was still wobbling. It took all her effort to keep upright.

A soft splash made Nina look around to see a second caiman surface at the other end of the chamber. It was even larger than the first, and seemed unconcerned about remaining unseen, floating on the surface like a log.

A log with teeth. It lazily opened its mouth, letting out a malevolent hiss.

Kari increased her pace. She was now halfway across, the beam drooping again under her weight. Every step made it sway a little more.

She could see the dagger clearly now. Its tip rested in a little metal cup that seemed to be connected to something behind the shallow recess. Another booby trap?

There was also a very narrow ledge just above the end of the beam, so thin she hadn’t been able to spot it until now. It was under a meter across and barely a centimeter deep, just enough to provide a toehold. It had obviously been placed there deliberately by the temple’s builders, but for now their reasoning remained unclear, and Kari had the distinct feeling she wouldn’t like the answer when it revealed itself-

The beam wobbled.

Her attention had been diverted by the mysterious ledge, just for a moment-but a moment was all it took for her to lose her balance. She tried desperately to straighten up, but her weight had already shifted too far over. In a second, she would fall into the pool, into the jaws of the waiting caimans-

She threw herself forward, grabbing the beam with both hands as she landed on her stomach. The narrow wood slammed against her like a truncheon blow. She clamped her knees around the shuddering walkway, trying to stop herself from rolling into the pool.

“Kari!” Nina screamed.

Chase pulled off his jacket, ready to jump in after her. “Shit, she’s not going to make it!”

The caimans, attracted by the noise, closed in.

“Stay back!” Kari shouted. Her knees were still in the water, but she managed to hook both her boots around the beam to drive herself forward.

The long head of the nearest caiman came fully out of the water, opening to expose its jagged teeth-

“Oi!” Chase roared, dropping onto the end of the beam and stamping one foot hard into the water, creating a huge splash. “Over ’ere! Hey!”

The larger of the two caimans changed direction with a flick of its tail, heading for him. The first, still gliding rapidly towards Kari, turned its head towards the noise-and took the heel of her boot against the side of its skull with a crack that echoed around the chamber.

The caiman released a sharp bark of air, thrashing its tail and dropping back into the water. Frantically, Kari hauled herself along the beam, looking back over her shoulder at the great reptile. It was circling in a sinister line through the water, arcing back around for her.

Chase kicked up another splash before leaping back onto the ledge as the caiman erupted from the water, its giant mouth agape. Powerful claws raked the stone wall as its heavy body thudded against the beam.

Kari was nearly jolted into the water by the impact. She clung to the beam with all her strength, the caiman crashing into it again and again in its attempt to pursue Chase, before it finally admitted defeat and dropped back into the pool.

The other caiman was still heading back at her, slimy water streaming from its mouth as it broke the surface. This time it had learned its lesson and was aiming for her upper body, out of range of her legs. Straining, she dragged herself forward again.

Her fingers touched cold stone, and she clawed for the tiny ledge, gaining just enough purchase to pull herself up from the beam and plant one foot upon it, thrusting herself upright.

The caiman lunged-

With a yell, Kari snatched the dagger from its resting place and plunged it down between the caiman’s malevolent yellow eyes, stabbing deep into its brain.

The reptile crashed onto the beam, then slid lifelessly back into the pool as she pulled the dagger out with a spurt of blood.

And where the blood blossomed in the dark water, it suddenly frothed, churned from below by dozens of fins.

Chase had been right.

Piranhas!

Kari flattened herself against the wall. One foot was on the beam, which juddered as the caiman’s body ground against it. The very tip of her other heel was on the little ledge. She waited until the beam stopped shaking, then looked around to see the result of removing the dagger. Something had definitely clicked when she’d grabbed it…

Two things happened at once.

From somewhere above Chase and Nina came a loud clang of metal. She caught a flicker of movement inside the opening Chase had seen, but it was too dark to make out the cause.

But she had no time to think about it, because the beam had started moving, retracting into the wall behind her. The supporting poles moved with it, slicing V-shaped ripples into the water-the whole thing was mounted on some sort of framework at the bottom of the pool, and now it was disappearing with alarming speed into the cold stone at her back.

“Eddie, do something, stop it!” Nina wailed, helpless as she watched the beam slide away from the side of the platform.

“How?” he demanded, looking for something, anything he could do to stop its relentless retreat. There was nothing.