After ten minutes, Grace reached the canyon rim. The wound in her side was bleeding. Ahead and just outside the tree line, a huge steel pipe, eight feet in diameter, emerged from the termination of the earthen berm and launched itself into space. It formed a span, a hundred feet long, to the rim of the opposite canyon wall. A gantry-style walkway was welded to the top of the pipe, and a flight of metal grid steps led up to it.

Grace eased closer, still staying within the cover of the forest. She leaned against a tree and studied the gantry.

One section of railing was missing at the far end on the downriver side, but otherwise the walkway seemed intact. Grace breathed a sigh. She crept forward to the edge of the woods. She wasn’t able to see very well on her own side of the river, upstream or down, but she spent long seconds studying the opposite cliff tops. There was no one in sight.

She took a deep breath and stepped into the open. Quickly, she mounted the steps to the gantry. She started across.

If it weren’t for a length of inch-thick steel pipe, Grace wouldn’t have heard the shot that erupted from the trees on the west rim of the canyon. As it was, she didn’t actually hear the silenced gunshot – only the sound of the heavy slug as it whined off the handrail next to her, missing her by millimetres.

Grace dropped to the catwalk. The wound in her side screamed with pain, but fear suppressed it. She pressed her face into the welded grid of the decking. The shot had come when she was nearly across. She estimated that she was about a dozen long paces from the eastern end of the gantry. There was another set of metal stairs there, on the upstream side of the pipeline. The side exposed to the gunman.

Grace edged her body toward the edge of the grid, desperately trying to find cover. Maybe she could take advantage of the curve of the pipe. The shooter would be lining up another shot.

The thought conjured the reality.

The bullet passed directly under her body, between the underside of the catwalk and the top of the giant pipe below. It slammed into the base of a stanchion, next to Grace’s right hip, and exploded in a shower of hot metal. The force of the impact jarred down the length of her leg and it immediately went numb.

That’s not Pendergast shooting, she thought. With a scoped rifle, he wouldn’t miss.

That’s Nader, using a handgun.

Grace felt a surge of hope. Nader would realise he was shooting from a bad angle. He’d have to stop firing while he worked his way along the top of the canyon wall to get closer. There was no trail there. She waited, dreading another shot.

Nothing.

Sensation was returning to her right leg, but now it was pulsing painfully, in tempo with the wound in her side. She wondered if she had taken some shrapnel from the last shot.

She heard the sound of something heavy moving through the bush on the west rim. Behind her, to the left. She’d guessed correctly. It was time to run. Praying that her leg wouldn’t give out, Grace lurched to her feet and sprinted for the end of the catwalk. A bullet whined off the big pipe a few yards ahead. Then another, close to her feet. She was abreast of the area with the missing railing and, in a blur, she glimpsed a flat table of dry stone.

The drop from the catwalk was at least ten feet. As another bullet ignited the air behind her head, she leaped.

In flight, she recalled the words of a sky diving instructor, years earlier, when she’d made her one and only jump.

Tuck and roll.

But this was solid granite.

The lower boughs of an old growth cedar overhung the rock table. Grace grabbed at the branches. They broke her fall, but they slashed the side of her neck and scraped the skin off her palms as she swung to the ground. Now oblivious to pain, she lunged into the cover of the woods. A bullet ripped through the branches inches above her head.

It wouldn’t be long before Nader crossed behind her. Grace wrenched the Beretta from her coat and took cover in a needle-carpeted hollow behind a tangle of roots. Steadying the gun with both hands, she aimed carefully at the far end of the gantry. The foresight on her gun’s barrel oscillated with her pounding heart. She tried to steady it by holding her breath. It didn’t seem to help.

She waited.