As Alexa fell, only an inch or two away from the building’s surface, glass and concrete raced past her cheek. Behind her, a bank of powerful multiton capacitors near the curtain wall should have fallen straight up along with her gravity field, slamming through the ceiling and across conduits that contained cabling that fed terawatts of electricity to the perimeter systems. That is, if their calculations were right . . .

She glanced between her feet as she heard a massive BOOM ten stories below. Incredibly a hole had blasted through the nanorod material and rippled through the concrete shell around it—scattering the concrete and glass like paper. A light brighter than the surface of the sun arced and crackled through the air. For a moment the entire downtown area was as bright as a sunny afternoon, replete with blue sky and clouds above. The light flickered on and off as if someone were riding the sun’s switch, and then a series of deafening booms pounded the air, shattering windows in the surrounding buildings hundreds of meters away. Another series of muffled booms in the interior of the BTC building rumbled ominously.

The shock wave raced after Alexa, stripping away the BTC’s facade as it came.

Alexa curved her direction of descent away from the building and fell away from it just as the glass disintegrated and the columns shattered. As she came out of a backward somersault and looked back, she noticed that the BTC headquarters building no longer looked like a boring 1960s building.

It looked like a forty-story black monolith from a Stanley Kubrick film, with a shimmering, translucent indigo-and-lavender energy field flowing over it. Suddenly the plasma field wavered, then winked out of existence, and she found herself staring at a smooth black rectangle, with concrete and glass debris still tumbling down onto the streets below. Car alarms wailed all over the city.

Cotton’s voice could barely be heard on her q-link. “That’s one scenario the AI designers hadn’t anticipated—total reversal of gravity. They’ve got a few work tickets now. Total perimeter defense failure.”

“I can see that, Cotton, thank you.”

“Triple redundant system failure. The hat trick.”

“There’s a curtain wall penetration from the blast around floor twenty.”

“I see it.”

“Way too hot, though. The entire facade on the north and south sides appears to have been stripped away in the blast.”

“That’s going to upset the greater Detroit tourism board.”

Alexa glanced around at thousands of blasted-out windowpanes in surrounding buildings. Glittering shards of safety glass were still plummeting down their sides like water in the reflected light of the BTC’s intense electrical fire. She shouted into her mike. “Get me my secondary target reference!”

“Right, my dear. Hang on.” A pause. “There.”

Alexa suddenly saw another red dot, this time just five floors below her and twenty floors above the electrical fire—which was still tearing at the fabric of reality and blacking out the optics on her visor’s autotint like a convention of welders. She could feel the heat from hundreds of meters away.

She lined up directly in front of the new reference dot about fifty meters away and drew her positron pistol. She pondered the setting, but then moved back another two hundred meters as she set it to full charge. “Breaching . . .”

Alexa aimed the pistol with both hands, and a millionth of a gram of antimatter shot down a laser-induced vacuum channel, impacting baryonic particles in the building’s surface and detonating the fabric of time-space with the force of ninety tons of TNT focused onto the head of a pin. Annihilating matter itself. Another blinding flash and a crack of thunder not unlike two mountains colliding as it blasted out any downtown windows left intact from the first blast.

The shock wave hit Alexa, sending her tumbling in midair. She immediately reversed gravity toward the epicenter of the blast. A piece of diamond aggregate howled past her like a Jet Ski–size bullet, boring a five-foot-wide hole through the middle of the Penobscot Building without so much as disturbing the surrounding masonry—and continuing to unknown consequences into the buildings beyond.

“What the hell did you just do?”

As glowing neon smoke cleared from the blast site, she could see a jagged five-yard opening blasted into the black surface of BTC headquarters. “I made myself a door. Proceeding to next objective . . .”

 • • •

Hedrick stared in amazement at a sprawling sea of red flashing alerts in the command center below as technicians and operations controllers ran frantically to emergency stations. He shouted to Morrison over the sound of Klaxon alarms. “What hit us?”

Morrison was tapping through holographic control screens. “Had to be a tactical nuke. Goddamnit! How did they get it in close enough? They probably shielded it in lead.”

A systems controller appeared in a holographic video screen at Hedrick’s elbow. “All surface perimeter defenses are down, Mr. Director.”

“How can they be down? How the hell could they be down? We have triple redundant systems.” Hedrick shouted at the ceiling. “Varuna! What the hell is going on?”

Varuna’s calm voice came in above the din. “All surface perimeter defenses have failed, Mr. Director.”

“How is that even possible?”

There was a surprising several-second pause as the AI apparently thought hard about something.

“The cause of the failure is unknown. Surveillance dust imagery shows capacitors one and five were torn from their mounts and hurled through levels twenty-one and twenty-two before contact was lost.”

A slow-motion three-dimensional hologram of the event was already playing before them. The image showed a sudden lurch as two massive cylinders leapt into the air, tearing mountings and conduits—and then all hell broke loose. The image then faded out.

Morrison fumed. “The blast must have dislodged them.”

“There’s no evidence of an external blast, Mr. Morrison. The capacitors were under a full charge and online when they sheared through power conduits carrying a terawatt of electricity from other systems. The breach in the nanorod perimeter wall on floors twenty-two and twenty-three is a result of an internal uncontrolled electrical discharge. Accelerometers on the machinery indicated they were in free fall when they detonated.”

Morrison narrowed his eyes. “Free fall. Someone knew right where to hit us. And I’ll bet I know who.”

“Gravity modification . . .” Hedrick pounded an intercom button. “We have enemies within our perimeter. I want them identified and eliminated. Activate automated interior defenses, and go into lockdown.”

Varuna’s calm voice said, “We are already in lockdown, Mr. Director.”

Suddenly another rumbling went through the building.

Hedrick looked at the ceiling of the command center. “What the hell was that—secondary explosions?”

One of the technical operations controllers tried to answer, but Hedrick shouted, “Let me guess: You don’t know. Get me some goddamned eyes outside.” Hedrick looked upward again. “Varuna, what was that?”

A holographic diagram of the building appeared before him, showing another hole punched in the north face of the building.

“The facility has just been hit on the north wall, floor thirty-six, by a powerful high-energy discharge that was neither nuclear nor chemical in nature.”

Morrison threw up his hands. “It’s Alexa. Goddamnit.” Morrison looked to the ceiling. “Varuna, were the blast and damage consistent with a positron weapon?”

“They were, Mr. Morrison.”

Hedrick held his head in his hands. “What do you want me to say? Have you never given a woman a gift you regret? It was a bad idea. Now let’s get that damned thing out of her hands.” He looked back up. “Varuna, what’s the current damage assessment?”