She reached the aft door of the plane, and ran inside. The unfinished widebody was huge and empty, a succession of dully gleaming curved arcs, like the belly of a metal whale. Halfway down, she saw a solitary Asian woman, attaching silver insulation blankets to the walls. The woman looked at Casey timidly.

"Is anybody else working here?" she said.

The woman shook her head, No. She looked frightened, as if she'd been caught doing something wrong.

Casey turned, ran back out the door.

Down below, she saw the men just one level beneath her.

She turned and ran up the stairs.

Into the hanging gardens.

The metal staircase had been ten feet wide when she started. Now it narrowed to two feet in width. And it was steeper, more like a ladder climbing into the air, surrounded by a dizzying crosswork of scaffolding. Power lines hung down like jungle vines on all sides; her shoulders banged into metal junction boxes as she scrambled higher. The staircase swayed beneath her feet. It turned abruptly at right angles every ten steps or so. Casey was now forty feet above the ground, looking down on the broad crown of the fuselage. And up at the tail, rising above her.

She was high up, and suddenly flooded with panic. Looking up at the men working on the rudder above, she shouted: "Hey! Hey!"

They ignored her.

Below, she saw the other two men pursuing her, their bodies intermittently visible through the scaffolding as they climbed.

"Hey! Hey!"

But the men still ignored her. Continuing upward, she saw why they had not responded. They were wearing audiopads, black plastic cups like earmuffs, over their ears.

They couldn't hear anything through them.

She climbed.

Fifty feet above the floor, the stairs abruptly angled right, around the black horizontal surface of the elevators, protruding from the vertical tail. The elevators obscured her view-of the men above. Casey worked her way around the elevators; the surfaces were black because they were made of composite resin, and she remembered she must not touch them with her bare hands.

She wanted to grab on to them; the stairs up here were not constructed for running. They swayed wildly and her feet slipped off the steps; she clutched at the railing with sweaty hands as she slid five feet down, before coming to a stop.

She continued upward.

She could no longer see the floor below; it was obscured by the layers of scaffolding beneath her. She couldn't see if the second shift had arrived or not.

She continued up.

As she went higher, she began to feel the thick, hot air trapped beneath the roof of Building 64. She remembered what they called this high perch: the sweatbox.

Working her way upward, she finally reached the elevators. As she continued above them, the stairs angled back now, close to the broad, flat, vertical surface of the tail, blocking her view of the men working on the other side. She no longer wanted to look down; she saw the wooden beams of the ceiling above her. Only five more feet… one more turn of the stairs… coming around the rudder… and then she would be-

She stopped, stared.

The men were gone.

She looked down and saw the three yellow hard hats beneath her. They were on a motorized lift, descending to the factory floor.

"Hey! Hey!"

The hard hats did not look up.

Casey looked back, hearing the clang of the two men still racing up the stairs toward her. She could feel the vibration of their footsteps. She knew they were close.

And she had nowhere to go.

Directly ahead of her, the stairs ended in a metal platform, four feet square, set alongside the rudder. There was a railing around the platform, and nothing beyond.

She was sixty feet up in the air on a tiny platform astride the huge expanse of the widebody tail.

The men were coming.

And she had nowhere to go.

She should never have started to climb, she thought. She should have stayed on the ground. Now she had no choice.

Casey swung her foot over the platform railing. She reached for the scaffolding, gripped it. The metal was warm in the high air. She swung her other leg over.

And then she began to climb down the outside of the scaffolding, reaching for handholds, working her way down.

Almost immediately Casey realized her mistake. The scaffolding was constructed of X-angled girders. Wherever she grabbed, her hands slid down, jamming her fingers into the crossjoint with searing pain. Her feet slipped along the angled surfaces. The scaffolding bars were sharp edged, difficult to hold. After only a few moments of climbing, she was gasping for air. She hooked her arms through the bars, bending her elbows, and caught her breath.

She did not look down.

Looking to her left, she saw the two men on the small high platform. The man in the red shirt, and the man in the baseball cap. They were standing there, staring at her, trying to decide what to do. She was about five feet below them, on the outside of the girders, hanging on.

She saw one of the men pull on a pair of heavy work gloves.

She realized she had to get moving again. Carefully, she unhooked her arms, and started down. Five feet. Another five feet. Now she was level with the horizontal elevators, which she could see through the crisscrossed girders.

But the girders were shaking.

Looking up, she saw the man in the red shirt climbing down after her. He was strong, and moved quickly. She knew he would reach her in just a few moments.

The second man was climbing back down the stairs, pausing now and again to peer at her through the girders.

The man in the red shirt was only about ten feet above her.

Casey went down.

Her arms burned. Her breath came in ragged gasps. The scaffolding was greasy in unexpected places; her hands kept slipping. She felt the man above her, descending toward her. Looking up she saw his big orange work boots. Heavy crepe soles.

In a few moments he would be stomping on her fingers.

As Casey continued to scramble down, something banged against her left shoulder. She looked back and saw a power cable, dangling from the ceiling. It was about two inches thick, covered in gray plastic insulation. How much weight would it support?

Above her, the man was descending.

The hell with it.

She reached out, tugged at the cable. It held firm. She looked up, saw no junction boxes above her. She pulled the cable close, wrapping her arm around it. Then her legs. Just as the man's boots came down, she released the scaffolding and swung out on the cable.

And began to slide.

She tried to go hand over hand, but her arms were too weak. She slid, hands burning.

She was going down fast.

She couldn't control it.

The pain from the friction was intense. She went ten feet, another ten feet. She lost track. Her feet slammed into a junction box and she stopped, swinging in the air. She lowered her legs around the junction box, gripped the cable between her feet, let her body weight go down-

She felt the cable pull away.

A shower of sparks flared from the box, and emergency alarms began to sound loudly throughout the building. The cable was swinging back and forth. She heard shouts from below. Looking down, she realized with a shock that she was only about seven or eight feet above the floor. Hands were reaching up to her. People shouting.

She let go, and fell.

She was surprised how quickly she recovered, getting right to her feet, embarrassed, brushing herself off. "I'm fine," she kept saying to the people around her. "I'm fine. Really." The paramedics ran over; she waved them away. "I'm fine."

By now the workers on the floor had seen her badge, seen the blue stripe, and were confused-why was an executive hanging from the gardens? They were hesitant, stepping away a little, unsure what to do.