One of the helicopters circling overhead among the television and police choppers dropped out of the sky, twin turbine engines whining. From concealed weapons pods blazed the unmistakable flashes of machine gun fire. Lead bullets slammed into the roof with the crack and smash of copper-clad death. Splinters of shattered wood and clouds of exploding concrete blossomed around Cap and Rock.

Cap drew first, whipping the odd black pistol from his holster. Rock-only an instant behind him-snapped the weapon up to aim at the killer swooping in from above. The pistols roared in powerful bursts, firing armor-piercing tracer bullets into the air.

An instant after firing, both men threw themselves aside and rolled out of the path of the oncoming machine gun blasts. Cap’s headband videocam flew from his skull, clattering across the bullet-riddled roof. The rounds tore apart the mystery camera and its satellite dish. Bits of glass, plastic, and aluminum flew everywhere, accompanied by copper swages and lead fragments from the bullets.

“Take this up your tailpipe, zhopu kozina!” Rock shouted, using his thumb to flip a switch on the pistol. Fully automatic now, the pistol fired a steady stream of tracers at the retreating helicopter. The orange-red streamers of color flew inexorably toward the aircraft.

Captain Anger joined in, his pistol still semi-auto. Each shot- though fired in rapid succession-was well-aimed, with Cap swiftly, reflexively calculating the proper angle of fire to ensure that bullet and chopper arrived in the same place at the same time.

Neither of the matte-black pistols ejected any brass casings. The weapons used caseless 10mm ammunition, which allowed for more than double the number of rounds in a magazine of similar size. And these pistols sported long, fat, double-column magazines, each holding forty-eight rounds, plus an extra one already chambered.

Rock’s volley and Cap’s more steadily paced stream of rounds hit the copter nearly simultaneously, peppering the fuselage with several direct hits. Undaunted, the aircraft rotated about for another assault.

With a loud curse, Rock realized that he had fired off his entire load. He ejected the magazine and drew a second from his ammo pouch, slamming it home and releasing the charger, which had locked open after the last round. There was no slide to drive home for there were no cases to eject. The weapon simply blazed out its projectiles without the chatter and rattle of conventional automatic weapons.

Cap still had half his ammo left. Carefully aiming each rapid shot, he squeezed off an even dozen at the onrushing helicopter. Every one hit their mark, punching twelve holes in the cockpit windshield. He avoided the fuel tanks, knowing that the tracer bullets could turn the onrushing aircraft into a fireball.

Rock blasted another deafening burst at the chopper, many of the fiery streaks making an impact on fuselage, rotor, and turbines.

“Run for it!” he shouted, scrambling to the left.

The chopper, its engines and murderous pilot both dead, hurtled toward them, a mass of metal, glass, and inflammable fuel. Cap estimated where it would hit and jumped far afield, running across the roof to the right and rear, practically under the advancing, falling machine.

With a shattering collision, it hit the edge of the building and tore out a section of the roof. Without even slowing, it dragged the debris along as it twisted and cartwheeled to the pavement four stories below. A sickening crunch of impact arose from the street.

Cap rushed to the demolished edge of the building to look down at the scene.

The helicopter lay in ruins a few yards in front of the advancing silver tide. The smell of spilled jet fuel rose from the wreckage. The other helicopters overhead-police and reporters-jockeyed for the best view of the disaster.

Without a word, Cap holstered his pistol and climbed down into the gaping wound in the side of the building. Rock followed, warily testing each shattered beam to ensure that it supported his not-inconsiderable weight. Cap moved with far more agility, maneuvering down the tangle of musty old wood and crumbling masonry like an experienced mountain climber on an alpine peak.

The damage reached to the windows of the second story. Cap gained his footing and paused on the ledge to search for a landing spot clear of detritus. After an instant’s deliberation, he lightly bounded from the ledge and plummeted feet-first toward the sidewalk. Extending his legs without locking his knees, he braced himself for the impact. Feet slammed against the concrete, powerful leg muscles contracted to absorb the energy of the fall. Like a cat he stayed on his feet, bending under the impact of a twenty-foot drop until his haunches very nearly touched his heels. Hands splayed, his fingertips hit lightly against the pavement to steady him and absorb the last few foot-pounds of energy from his fall.

From that position, he leapt forward like an Olympic sprinter, leaving Rock on the second story to contemplate a less drastic method of reaching ground level.

Captain Anger bounded over to the crushed bubble of the helicopter. Tearing open the door with one mighty hand, he reached in with the other to feel the throat of the blood-spattered corpse inside. Cap regretted the death of someone who could have provided valuable information. A quick pat search of the body turned up no identification. Cap’s hand came up from its exploration smeared with kerosene and lifeblood.

He turned the man’s head up; having lost his videocam on the roof, he memorized every feature that might still be recognizable. One ten-millimeter slug had hit the pilot in his jaw, shattering the bone and rendering the lower part of his face an unidentifiable red mess.

“Cap!” Leila cried. “Get out now!”

Cap’s gaze darted around the ruined aircraft interior, lighting upon a set of Jeppesen air charts. He seized the binder and jumped back out of the copter just as the advancing microbotic sea engulfed the wreckage.

The force of his retreat threw him back against the curb. With grunt, he stood and watched the blob overrun the helicopter, coating it as if an invisible artist electroplated everything in sight with a silver patina. Its contours softened. Within less than a minute, the billions of microbots devoured the obstacle and reduced it to microscopic bits. The minuscule electro-mechanical creatures utilized some of the chemicals-the kerosene and oil in the turbine engines, the glucose and oxygen in the pilot’s flesh and blood-as fuel. Some-the silicon in the electronics, the steel and aluminum in the fuselage-they used to build more copies of themselves.

They moved westward with unstoppable vehemence.

Captain Anger eyed the colony of artificial life coolly, considering his options.

Rock managed to kick in a second story window, climb through, and rush down to join his compeer. He skidded to a halt beside Anger and gaped in renewed awe at the voracious slime, allowing to slip from his tongue on of the few pieces of English slang he’d bothered to incorporate into his vocabulary.

“Geez, Cap,” he said, “that stuff’s hungry!”

A truck skidded around the corner at the west end of the street. Cap eyed it with relief. “Here comes an appetite suppressant.”

A harried young man jumped out of the driver’s seat and bounded over to Dr. Bhotamo. Cap and Rock set to unloading the truckload of cryogenic material. Firemen and police joined in-nervously-and within minutes they had surrounded the moving lake with a perimeter of large dewars-insulated fifty-five-gallon drums.

At Captain Anger’s request, the driver from Lawrence Livermore Laboratory handed the cryogenic suits to Rock and Leila. The thick, layered suits-similar to the suit Cap wore, if less versatile-glittered with a reflective coating of silvered Mylar. The three, when fully suited, looked like living extensions of the mirror pool. They surrounded the westward-moving lake at equidistant points, each standing near a drum of liquid nitrogen and holding a cryogenic spray gun.