They tumbled and hit the water together with a loud splash. Summer tried to swim deep, kicking away from the guard. But he maintained his grip on her leg while using his other hand to swing the butt of his pistol at her. She felt like she was in an underwater wrestling match. Figuring that she was the better swimmer, she stroked deeper while kicking to break free of his grasp.
Her hand slapped against the dam and she felt the concrete surface skim across her fingers. The movement was faster than she expected. They were being pulled by a strong underwater current. As the water rapidly darkened, she realized they were being drawn down toward the base of the dam.
A new worry filled her senses. What was causing the undertow? There was no powerhouse or external water flow out the back side of the dam. Absent a spillway, there should have been nothing dangerous about diving down the dam’s interior face.
The fear of drowning overtook her fear of the guard. She relaxed in his grip and then aligned with his efforts to kick to the surface. But the water turned darker, and an increasing pressure in her ears told her they were being drawn deeper into the lake.
Through the murky water, Summer detected a circular opening, about fifteen feet in diameter, that was sucking them toward it. She realized it was a spillway, cut through the base of the dam. The Zimapán Dam had in fact been built to generate hydroelectric power, only its generating station was located at the end of a tunnel some thirteen miles downstream.
The spillway inlet had a grate to keep out large debris, but years of neglect had left it mangled. Nearly half of the grate had been battered inward, allowing an unfettered flow of water.
Summer and the guard saw what was coming and fought to swim clear. But the suction grew stronger, pulling them faster to the opening. Abandoning her instincts, Summer did the unthinkable. She swam toward the inlet.
The guard glanced at her in disbelief, panic filling his eyes as he fought the relentless pull. Too late, he realized Summer had made the smart move. Swimming hard with the flow, she angled across the current just enough to reach the intact section of grating. She snared a metal crossmember and yanked her body toward it.
She slammed against the grate, nearly knocking the last breath from her lungs. The water pressure pinned her alongside some logs, a tire, and other debris. She turned her head as the guard came hurtling past. His scarf and sunglasses had long since been ripped away, and Summer saw the stark terror in his eyes as he failed to break free of the suction. In an instant he was gone, sucked down the black hole where the swirling waters drowned his final screams.
At least someone will be able to recover my body, Summer thought as a yearning for air overpowered her senses.
Clinging to the grate in final desperation, she wondered what was happening atop the dam and if her brother was still alive.
21
Dirk was very much alive, despite a pounding heart and aching lungs. More by luck than ballistic trajectory, he had launched the van off the bluff and onto the path of the fleeing Jeep, aided by a rock on the accelerator and a rope holding the steering wheel. He didn’t wait for the dust to settle before sprinting downhill in pursuit.
He had to backtrack a hundred yards to find a path to the road below. The gradient would have been precarious for someone in hiking boots but was borderline suicidal for someone at a full run wearing water shoes. Several times Dirk lost his footing, tumbling and sliding down the loose terrain. Only his wetsuit protected him from serious injury.
During his descent, he could not see the dam and could only hope the Jeep would still be there. Not that he had a plan of any sort. Weaponless against armed men, he had little hope of stopping them. But he had to find out if Summer was with the men — and still alive.
As he neared the bottom of the cliff, he caught sight of the dam and nearly froze. Summer was standing near the crumpled van. Suddenly she leaped into the lake with a gunman in tow. Distracted by the sight, Dirk lost his footing and fell hard down the hillside.
The tumble cost him valuable seconds. By the time he regained his footing, the Jeep had squeezed past the overturned van. The driver stopped and peered into the water. He stared a moment, then shook his head. Seconds later, the tires spun and the Jeep shot across the dam, its rear end weighed down by the stolen artifact.
Finally reaching the road, Dirk raced to the dam. Blocked by the battered van, the Jeep’s driver never noticed him in his mirror as he drove up the hill. At the smashed vehicle, Dirk peered into the water. Calm and flat, it gave no indication of the human turmoil below.
He raced to the van and pried open a rear door. The interior was a jumbled mess, but he found Summer’s dive tank, BC, and mask. He slipped on the equipment and popped open the tank’s K valve. Something nagged at him and he retrieved the rope. One end was still secured to the doorframe, so he tied the loose end to a D ring on his BC. Hopping over the rail, he plunged into the cool lake.
He flicked on a small light attached to the BC and followed a trail of sediment particles rushing into the depths. Soon he felt the pull of the current. He kicked hard, accelerating with it while searching for Summer.
Still pinned to the grate, she had managed to pull herself to its upper edge. She had been underwater for more than a minute and was approaching a state of hypoxia.
Had there been a ladder or anything else to grip, she might have pulled herself clear of the suction, but all she found was the smooth face of the dam. A flood of desperate, confusing thoughts surged through her mind, pleading for her to try to escape. Perhaps there was hope at the other end of the spillway? She began prying her fingers off the grate when something caught her eye.
A faint light came from above. The light quickly grew brighter until it was joined by a figure flying toward her. Hope and agony struck simultaneously as she recognized Dirk rushing past her and through the open grate. Oddly, his eyes seemed to smile as he vanished into the black hole.
An instant later, she saw the light wavering in the spillway. Through its flashes, she detected a taut rope leading from her brother up to the surface. He reappeared a moment later, hoisting himself hand over hand until reaching the top of the spillway opening. Summer was a few feet to his left, frozen to the grate, her face turning blue.
Bracing his feet against the concrete surface, he pushed off with all his might, springing toward his sister. He released one hand from the rope and reached for her torso. Feeling his touch, she grabbed his hand, then wrapped her arms around his waist.
She yanked the regulator out of his mouth and jammed it into her own, sucking deep breaths. Dirk inflated his BC, pulled them a few feet up the rope, and waited for Summer to pass back the regulator. They shared the tank’s air as Dirk muscled them up the face of the dam. The spillway’s suction gradually waned until they could kick to the surface.
“That was a nasty surprise down there,” Dirk said after they broke into the sunshine.
“You’re telling me. I was about two seconds away from finding out what’s at the other end of the spillway.”
“Likely the spinning turbines of a hydroelectric plant.”
Summer shuddered at the fate of the gunman who had been sucked through the tunnel. “I think I’ve had my fill of this reservoir.”
She swam to the side of the dam, grabbed the rope, and hoisted herself up. Dirk followed suit, gladly ditching the tank and BC when he reached the van.
Summer gazed at the empty road that curved up the hill. “They shot and killed Dr. Torres, then stole the stone.”