Drivers continued maneuvering the huge trucks, efficiently form-ing a barrier blocking the scene of action from the crowd's view.

Bronschweig disappeared into the melee. When he reached the tanker trucks he ducked between them and surreptitiously withdrew a cell phone. His face tight, he punched in a number, waited, and then spoke.

"Sir? The impossible scenario we hadn't planned for?" He listened for a moment, then replied tersely,

"Well, we better come up with a plan."

<>

CHAPTER 2

FEDERAL BUILDING DALLAS, TEXAS

One week later, fifteen agents in dark wind-breakers emblazoned with the letters FBI watched impassively as another helicopter hov-ered above them. They stood in seemingly ran-dom formation on a rooftop, their eyes shielded by reflective sunglasses, faces uniformly expres-sionless. At the sides of a half-dozen of them, leashed Dobermans and German shepherds lolled exhausted, tongues hanging out as they vainly sought relief from the shimmering heat of midday. When the chopper touched down, the dogs flattened their ears against their skulls, but otherwise took no notice. A moment later the helicopter's side door was flung open, and a single man emerged. Hatchet-faced, his eyes narrowing as he took in the men and women waiting on the roof, Special Agent-in-Charge Darius Michaud paused, then walked authorita-tively toward them.

"We've evacuated the building and been through it bottom to top." One of the agents met him, cell phone in hand, and motioned at the sweep of gray roof around them. "No trace of an explosive device, or anything resembling one."

Michaud looked at him, his mouth tight. "Have you taken the dogs through?" The agent nodded.

"Yes, sir."

"Well, take them through again." For an instant the agent stared at him, unable to hide the weariness in his face. Then, "Yes, sir," he replied, and turned back to his charges.

Behind him Michaud turned and scanned the horizon, his hands linked behind his back.

For a minute or two he stood like this, register-ing the familiar silhouette of the Dallas skyline, the flat silvery expanse of cloudless sky beyond and the dull array of ladders and turbines and concrete atop the adjacent skyscraper.

Suddenly he stiffened. Shading his eyes with his hand, he walked slowly to the edge of the roof, leaning against the barrier there. He said nothing, but the line of his mouth grew even tighter as he stared to where a solitary fig' ure emerged from a door on the neighboring roof. Even from this distance, he could see the resolve with which the slender form moved beneath its FBI windbreaker, and the glint of sunlight on her shoulder-length auburn hair. Michaud's hands clenched at the edge of the wall.

On the other rooftop, Special Agent Dana Scully winced as the door slammed shut behind her. Her finger jabbed at her cell phone as she stepped carefully down the stairs and onto the roof, looking around warily.

"Mulder?" she said urgently, the cell phone cool against her cheek as she paused. "It's me."

Mulder's voice echoed tinnily in her ear. "Where are you, Scully?"

"I'm on the roof."

"Did you find anything?"

She brushed a drop of sweat from her nose. "No. I haven't."

"What's wrong, Scully?"

Scully drew herself up and shook her head impatiently, as though Mulder stood in front of her and not somewhere on the other end of a cell phone. "I've just climbed twelve floors, I'm hot and thirsty and I'm wondering, to be hon-est, what I'm doing here."

"You're looking for a bomb," Mulder's un-flappable voice replied.

Scully sighed. "I know that. But the threat was called in for the federal building across the street."

"I think they have that covered."

Scully grimaced even more impatiently. She took a deep breath and began, "Mulder, when a terrorist bomb threat is called in, the logical pur-pose of providing this information is to allow us to find the bomb

. The rational object of terrorism is to provide terror. If you'd study the statistics, you'd find a model behavioral pattern in virtu-ally every case where a threat has turned up an explosive device—"

She paused, and drew the cell phone closer, choosing her words as carefully as though she were explaining something to a rather slow, stolid child. "If we don't act in accordance with that data, Mulder—if you ignore it as we have done—the chances are great that if there actu-ally is a bomb, we might not find it. Lives could be lost—"

She paused again for breath, and suddenly realized she'd been the only one talking for the last few minutes. Her voice rose slightly as she said, "Mulder… ?"

"What happened to playing a hunch?"

Scully almost jumped out of her skin: the voice came not from her cell phone but from two feet away.

There, in the shadow of the AC unit, stood Fox Mulder. He raised an eyebrow almost imperceptibly as he cracked a sunflower seed between his teeth, tossing the spent husks to the ground as he clicked off his cell phone and stepped toward her.

"Jesus, Mulder!" Scully moaned, shaking her head.

"There's an element of surprise, Scully," said Mulder evenly. "Random acts of unpre-dictability."

He popped another sunflower seed into his mouth as he went on, "If we fail to anticipate the unforeseen or expect the unexpected in a universe of unforeseen possibilities, we find ourselves at the mercy of anyone or anything that cannot be programmed, categorized, or easily referenced…"

As he spoke he walked toward the edge of the building. At the wall he leaned over, sail-ing his sunflower seeds off into the air and then dusting his hands off. For a moment he paused, staring thoughtfully, almost wistfully, into the nether distance, then turned to Scully and said, "What are we doing up here? It's hotter than hell."

And before Scully could make an exasper-ated reply he was off again, striding gracefully toward the stairs where Scully had emerged a few minutes before. She stood and watched him, then stuffed her cell phone into a pocket. Hiding a grin, she followed him, grabbing his arm and steering him up the steps.

"I know you're bored in this assignment," she said. Any faint vestige of humor leaked from her face.

"But unconventional thinking is only going to get you into trouble now."

Mulder looked at her impassively. "How's that?"

"You've got to quit looking for what isn't there. They've closed the X-Files, Mulder. There's procedure to be followed here. Protocol," she added, giving the word a threatening emphasis.

Mulder nodded as though weighing her advice. Then, "What do you say we call in a bomb threat for Houston," he suggested, tilting his head to one side. "I think it's free beer night at the Astrodome."

Scully set her mouth and gave him a look, but it was no use. Sighing, she hurried past him up the stairs, took the last few steps until she stood at the top, and grabbed the doorknob. She twisted it, once, twice, futilely; and looked back at Mulder.

"Now what?" she demanded, her face grim.

Mulder's impish expression vanished. "It's locked?" he asked edgily.

Scully looked at him and wiggled the knob again. "So much for anticipating the unfore-seen…"

She squinted up at the sun, then gazed at Mulder. Before she could say anything else, he lunged past her, yanking her hand from the knob. He turned it, and the door opened eas-ily.

"Had you." Scully smirked, leaning against the wall.