Existence

society must count on a second line of defense.

Us.

It meant-Tor knew-that any citizen could wind up being a soldier for civilization, at any time. The way they made the crucial difference on 9-11 and during Awfulday.

In other words, expendable.

“That one.” Warren chose, and moved toward the nearest green-tinted cell.

Though she had doffed her specs, there was still a link. The smart-mob’s voice retained access to the conduction channel in her ear.

“Tor,” said the group mind. “We’re getting feed through Warren’s goggles. Are you listening? There is a third possibility, in addition to helium and hydrogen. Some of the cells may have been packed with-”

She bit down twice on her left canine tooth, cutting off the distraction in order to monitor her omnisniffer. She inhaled deeply, with her eye on the indicator as Warren made a gliding, slicing motion with his cutter.

The greenish envelope opened, as if along a seam. Edges rippled apart as invisible gas-appreciably cooler- swept over them both.

HELIUM said the readout. Tor sighed relief.

“This one’s not poisonous.”

Warren nodded. “But no oxygen. You can smother.” He ducked his head aside, avoiding the cool wind, and took another deep breath of normal air. Still, his next words had a squeaky, high-pitched quality. “Gotta move fast.”

Through the vent he slipped, hurrying quickly to the other side of the green cell, where it touched one of the great chambers of hydrogen.

Warren made a rapid slash.

Klaxons bellowed, responding to the damage automatically. (Or else, had the company chosen that moment, after several criminally-negligent minutes, to finally admit the inevitable?) A voice boomed insistently, ordering passengers to move-calmly and carefully-to their escape stations.

That same instant, the giant hydrogen gas cell convulsed, twitching like a giant bowel caught in a spasm. The entire pinkish tube-bigger than a jumbo jet-contracted, starting at the bottom and squeezing toward a sudden opening at the very top, spewing its contents skyward.

Backwash hurled Warren across the green tube. Tor managed to grab his collar, dragging him out to the walkway. There seemed to be nothing satisfying about the “air” that she sucked into her lungs, and she started seeing spots before her eyes. The little man was in worse shape, gasping wildly in high-pitched squeaks.

Somehow, Tor hauled him a dozen meters along the gangway, barely escaping descending folds of the deflated cell, till they arrived at last where breathing felt better. Did we make any difference? she wondered, wildly.

Instinctively, Tor slipped her specs back on. Immersed again in the info-maelstrom, it took moments to focus.

One image showed gouts of flame pouring from a hole in the roof of a majestic skyship. Another revealed the zeppelin’s nose starting to slant steeply as the tug-locomotive pulled frantically on its tow cable, reeling the behemoth toward the ground. Spirit resisted like a stallion, bucking and clinging to altitude.

Tor briefly quailed. Oh Lord, what have we done?

A thought suddenly occurred to her. She and Warren had done this entirely based on information that came to them from outside. From a group-mind of zeppelin aficionados and amateur scientists who claimed that a lot of extra hydrogen had to be going somewhere, and it must be stored in some of the former helium cells.

But that particular helium cell-the one Warren sliced-had been okay.

And now, amid all the commotion, she wondered. What about the smart-mob? Could that group be a front for clever reffers, who were using her to do their dirty work? Feeding false information, in order to get precisely this effect?

The doubt passed through her mind in seconds. And back out again. This smart-mob was open and public. If something smelled about it, another mob would have formed by now, clamoring like mad and exposing the lies. Anyway, if no helium cells had been tampered with, the worst that she and Warren could do was bring a temporarily disabled Spirit of Chula Vista down to a bumpy but safe landing atop its tug.

Newsworthy. But not very. And that realization firmed her resolve.

Tor yanked the attendant onto his feet and urged him to move uphill, toward the stern, along a narrow path that now inclined the other way. “Come on!” she called to Warren, her voice still squeaky from helium. “We’ve got to do more!”

Warren tried gamely. But she had to steady him as the path gradually steepened. When he prepared to slash at another green cell, farther aft, Tor braced his elbow.

Before he struck, through the omniscient gaze of her specs, Tor abruptly saw three more holes appear in the zep’s broad roof, spewing clouds of gas, transparent but highly refracting, resembling billowy ripples in space.

Was the zep company finally taking action? Had the reffers made their move? Or had the first expulsion triggered some kind of compensating release from automatic valves, elsewhere on the ship?

As if pondering the same questions, the voice in her jaw mused.

“Too little has been released to save the Spirit from the worst-case scenario. But maybe enough to limit the tragedy and mess up their scheme.

“It depends on a rather gruesome possibility that one of us thought up. What if-instead of hydrogen-some of the helium cells have been refilled with OXYGEN? After experimenting with a similar, programmably permeable polymer, we find that the fuel replenishment process could be jiggered to do that. If so, the compressed combination-”

Oxygen?

Tor shouted “Wait!” as Warren made a hard stab at one of the green cells, slicing a long vent that suddenly blurped at them.

This wave of gas wasn’t as cool as the helium had been. It smelled terrific, though. One slight inhale filled Tor with sudden and suspicious exhilaration.

Uh-oh, she thought.

At that moment, her spectacle-display offered a bird’s-eye view as one of the new clouds of vented hydrogen contacted dying embers, atop the tormented Spirit of Chula Vista.

Like a brief sun, each of the refracting bubbles ignited in rapid succession. Thunderclaps shook the dirigible from stem to stern, knocking Tor and Warren off their feet.

Is this it? Her own particular and special End of the World? Strangely, Tor’s clearest thought was one of professional jealousy. Someone down below ought to be getting truly memorable and historic footage. Maybe on a par with the Hindenburg Disaster.

This was the critical moment. With their plan dissolving, the reffers must act. Any second now, a well-timed chain explosion within the Spirit’s great abdomen…

While the violent tossing drove Tor into fatalism, all that invigorating oxygen seemed to have an opposite effect upon Warren, who surged to his feet, then slipped through the tear that he had made and charged across the green cell, preparing to attack the giant hydrogen compartment beyond, heedless of the smart-mob, clamoring at him to stop.

Tor tried to add her own plea, but found that her throat would not function.

Some reporter, she thought, taking ironic solace in one fact-that her specs were still beaming to the Net.

Live images of a desperately unlikely hero.

Warren looked positively giddy-on a high of oxygen and adrenaline, but not too drugged to realize the implications. He grimaced with an evident combination of fear and exaltation, while bringing his cutter-tool slashing down upon the polymer membrane-a slim barrier separating two gases that wanted, notoriously, to unite.

* * *