"At least let me accompany you. I am more capable than your low-level suit assists. Also, if you are terminated and I am later recovered, I shall be able to make a full report."

"What a cheerful notion."

"I am simply trying to fulfill my autofac-implanted imperatives, Peej...."

"All right." Dos Santos stepped to the console and ejected the kibe, a featureless silver wafer the diameter of a hockey puck, but only half as thick. Fitting it flat into the appropriate sticktite slot on his harness, he turned to leave the disabled ladybug.

"I am now fully integrated with your suit sensors, Peej. They are of high quality."

"I have a feeling we'll need them," said Dos Santos. "Activate my retinal displays, please."

"Done."

Dos Santos's peripheral vision filled with translucent shimmerstats, and he stepped tentatively into the jungle.

2. Infoslam

The first report indicating that something was seriously wrong with River Seven had come a mere twelve hours ago, emanating from the kibe unit captaining one of the numerous floating autofacs-cum-general-stores that supplied the indigenous Riverside population. The unit, a mere hundred klicks from Machine Lake, had messaged that the River's downstream velocity was decreasing radically, dropping toward ancient baseline values or below; probes launched into the upstream side, however, still registered normal values.

Continued updates revealed a steady decline in the force of the artifical current.

When other reports from further downRiver began to flood in -- a tourist vessel, a passenger ferry, a fleet of sport skimmers and striders -- it became obvious to Dos Santos that River Seven -- his River -- was dying.

Naturally, he had been in Lagos on official business at the worst possible time. Had the trouble found him at his normal post -- his HQ on the shores of Machine Lake -- he would have been at the source of the problem and able to take immediate action. As it was, a long trip back had been necessary first.

Now, knowing that his craft had been sabotaged, it became obvious that the attack on River Seven had been timed to take place in his predictable absence....

Toward the unexpected abrupt end of his flight, Dos Santos knew that the downstream portion of River Seven must have been approaching total shutdown.

The death of the current, as he had plotted it in Lagos, had been propagating faster than the current itself, a shut-down message of some unknown sort, passed from one flagellum-flailing silicrobe to its neighbor, and then to its neighbor's neighbor, thus outracing the physical flow as a sheer information wave.

The continued functioning of the upstream third of River Seven was explainable by the deliberately engineered lack of communication between the two currents. Only along the nearly 2000 klick length of the upstream-downstream interface, where a thin layer of specialized downstream silicrobes performed an elaborate ciliary doesy-doe with a matching layer of upstream silicrobes, exchanging energy in a friction eliminating dance, did any mixing occur. And the incompatible nature of the two currents, designed to avoid command snafus, had apparently succeeded in keeping the upriver current alive a little longer.

But the ultimate source of upriver silicrobes was the downstream current, and the death of the smaller, still functioning portion of River Seven was inevitable.

From the feedstocks of Machine Lake were born all the silicrobes which comprised 50 percent by volume of the downstream River Seven channel. (The other half of the downstream channel was the traditional H2O from traditional sources: feeder streams, rainfall, underground aquifer connections. The missing volume of water had been long ago diverted for human consumption.) From Machine Lake the silicrobes exited, mingling with the available water in a synthetic gunmetal-colored broth. (Nanosmall, the silicrobes were of course invisible individually, presenting an homogenous appearance en masse.)Programmed to churn downstream at a steady speed, each maintaining a constant distance from the downstream shore and its neighbors, the silicrobes carried the water molecules along with them faster than mere gravity ever had.

At the mouth of River Seven, the fingerlike delta around Port Harcourt, the downstream silicrobes were triggered by the increased salinity and by info from GloPos navsats, undergoing the transformation into upstream silicrobes.

Separating from their partnered water molecules (which continued out to sea as of yore), the upstream silicrobes made a coherent U-turn and headed back.

Without H2O partners, they needed a virtual channel only half the size of the downstream one to make their way back to Machine Lake and resorption. Upstream speed was 80 percent of the downstream current.

Except today.

3. Big Muddy The last chunky frondtree fell to Dos Santos's flashlight-machete with a sound like a watermelon hitting the floor from table-height, and sticky juice propelled by xylemic pressure sprayed his face and millipore suit. Then he stepped out of the jungle and onto the staymown vetiver turf of River Seven's upstream bank.

"Peej -- suit bladders are now full with purified water, and any further dermal suit-contamination will have to be exosonically evaporated."

"Fine, fine," said Dos Santos absentmindedly, his entire concentration, basal and add-on, devoted to his ailing wide River.

The bipartite line of hyperfluid was dramatically sick.

Consider the more distant downstream side.

From its border with the upstream virtual channel all the way to the far bank, the downstream two-thirds of the River was a stagnant dove-grey stripe.

The deactivated silicrobes, apparently still remaining in suspension, now no longer contributed any motion to the flow and in fact hindered the water molecules from resuming even their old basal speed. The downstream waterway, until so recently an efficient Riverroad upon which millions relied, was now a turbid slurry.

Dos Santos looked to the left, downstream, but focused his gaze on the nearer third of the River, the upstream channel.

This portion of River Seven was still functioning. Being composed of pure silicrobes, it was matte black in color and stood out sharply, its border still cohesive, from the downstream mess. But this normal appearance was misleading, and Dos Santos knew-- With a sharp intake of breath, the River Master spotted it.

The failure wavefront.

He watched helplessly as the killer disinformation propagated swiftly upriver, soon reaching his position and passing unstoppably on.

Behind it, silicrobes went offline by the hundreds of trillions. The black stripe instantly began to extend irregular fingers of darkness into the downstream portion of the River, silicrobes flowing "backwards," and from greater concentration to lesser as the now-unthinking River -- formerly considered an actual entity of Turing Level One -- attempted to homogenize itself according to dumb physics.

"Damn. Damn, damn, damn!"

Momentary hopelessness washed over Dos Santos. He had dedicated his life to Riparian Admin, out of a love for these great semiliquid, semi-intelligent transport machines. For the past fifty years, he had worked self-sacrificingly on the Rivers of the world, the large and the small. River Eight (the old Volga), River Three (the old Mississippi), River One-Oh-Four (the old Ganges), River Twenty-Nine (the old Nile), even River One (the old Amazon) -- First as apprentice, then as journeyman, finally as Master, he had lovingly tended these sinuous creations of humanity that snaked across the domesticated globe, carrying mankind's freight and travelers, hosting its recreations, bathing its pilgrims. And never in that time had he experienced such a thing as this horror: the death of one of his charges. It felt like he imagined the death of the never-met pairbond proxy and hypothetical zygotes he had never permitted himself to indulge in would have felt. There was a hole in his soul.

Anger and a determination for revenge replaced the hopelessness. Dos Santos would make someone pay.

And River Seven, he vowed, would live again.

He advanced to the edge of the banking, which sloped away steeply to the River, a forty-five degree stretch of crumbly red clay, and scrambled down.

A rush of small dislodged pebbles tumbled down to the River surface and sat atop the high-density gel-like silicrobe liquid, each rock centered in its own surface-tension dimple.

The kibe sounded alarmed. "Peej Dos Santos, you do not intend--"

Dos Santos reached the marge of the River and squatted down. The pebbles were drifting downstream.

"Quiet! If you want to be useful, prepare to analyze some telemetry."

After peeling off both gloves, the River Master inserted his hands into the stagnant silicrobe soup.

The shimmerstats boiled with metagrafix in the corners of his eyes, fed by the subdermal mycotronix digiface sensors in his fingertips. Tapping the feed, the kibe added its verbal interpretation.

"It appears that the River has been contaminated with a dose of high-velocity instruction ribozymes based on the standard stepdown routines, but with subtle alterations that are not readily decodeable. The silicrobes are merely offline and apparently undamaged. If we could denature the invader, it would be a simple matter to restart the River--"

Dos Santos stood. "We'll have to do it fast, though, and that means getting to the facilities at Machine Lake. Not only do we have to worry about the possibility of further attacks, but there are system constraints as well.

Eventually, the 'crobes are going to drop out of suspension and settle to the bottom. A restart under those conditions would be chaotic. We'd kick up enough particulates to clog the whole delta and probably kill off all the lifeforms as well. And if the mixing of upRiver and downRiver 'crobes continues, the vortices that'll form on a reboot will be orders of magnitude larger than normal--"

The kibe interrupted. "Speaking of vortices, Peej, here comes a Vortifish Hunter right now!"

4. Old Man River The coracle glittered nacreously, catching glints of African sunlight, an upturned halfshell with rippled, purpled rim. (Its original seedstock, highly modified of course, had been the chambered nautilus.) Large enough to hold two basal humans, it now contained only one sophont, a cynocephali wearing a loin covering of plaid clothtree fabric.

Originally the cynocephali -- or Anubians -- had been bred and released only along River Twenty-Nine, the old Nile. Part tourist attraction, these bipedal dog headed sophonts had been designed to occupy a new top niche in the food chain. So successful and popular had they proven that no River today, some ten Anubian generations later, was without them.

The furred humanoid splice stood at the rear of its tiny craft, the tiller that controlled the steering jets in its paw. It sailed midway down the former upstream channel whose black syrupy components were now uselessly and slowly heading downstream with all the rest.

The small vessel was plainly bearing toward Dos Santos.

As the craft drew nearer, Dos Santos could make out further details, including grown-bone spears racked across the bow. And as the lone sailor expertly beached its craft, Dos Santos recognized the tattoon icon beneath the skin of one canine ear as the mark of the Hyena Tribe of Vortifishers.

"Peej Human!" barked the splice, showing sharp teeth webbed with saliva.

"Our River dying!"

At that moment, the kibe announced, "Incoming transmission via GlobalTelesis for the River Master."

"Accept."

The pleasant female voice of his Fon apprentice, Isoke, whom he had left behind in Lagos, sounded in Dos Santos's right ear like a beacon from a saner world.

"Norodom! The saboteurs have been pinged and popped! They were greenpeacers calling themselves the Izaak Walton League. Only ten human members, but they managed to kill several Rivers and disrupt half the world's gross shipping tonnage! Dai Ichi Kangyo has just issued an estimate of five billion time dollars worth of loss. But the crickcops and the IMF blueboys are certain they've slagged them all! You shouldn't have to worry about another disruption."

As always, hearing Isoke's eager voice and realizing his responsibilities to her, Dos Santos tried to imagine how Master Trexler would have responded.

"That's wonderful, Isoke. But we're still left with the problem of getting Number Seven up and running."

"Can't you just dump the Instruction Set into the River right where you are?"

The Master patiently explained to his apprentice about the need to denature the ribozyme contaminants with the Machine Lake equipment first.

Mixing the Instruction Set with the contaminant would simply produce undifferentiated glop.

"What can we do then? You were right about the remaining ladybugs being sabotaged just like yours. The RA has no other transports available. We can hire a private thopter or borrow a government one, but it'll take hours to get to you, even from the closest point. You're deep into the low-tech preserve around the Lake...."

Dos Santos considered the Vortifisher standing before him. The splice's mouth gaped open, tongue hanging as it panted nervously. Muscles beneath its spotted coat twitched.

"I think I have transportation. It's slow, but it's worth a shot. Send out a flier as backup, though. Tell it to look for me on the River."

Signing off, Dos Santos addressed the Hyena.

"Can your boat make it to Machine Lake?"

The Hyena smiled. "This is good boat. Humans made this boat. Never stops!

Eats River and spins tail, all day. Fast, fast, fast!"

"How fast?"

This question brought a frown to the cultivar's canine face. After pondering a moment, it answered. "See that clo'tree? Here to there, ten breaths."

"Twenty knots," interpolated the kibe.

Dos Santos hissed. "Two hours or more to the Lake! It'll have to do.

Let's go."

Dos Santos and the splice pushed the beached coracle off, then jumped in.

The Hyena prodded control ganglia on a hump near the tiller, and the organic motor came to life. An intake on the bow fed silicrobes -- online or off, it mattered not -- to the org-engine which broke them down and stole their ATP.

The thick, whiplike macroflagellum at the rear of the craft soon had them up to full speed.

"We stop at my village and tell pack where I go."

Dos Santos opened his mouth to argue, then thought better of it. The splice's teeth, not to mention its spears, gave the River Master pause, despite the comforting presence of his Intratec pistol. Although human-designed, this was no collar-wearing domestic cultivar, but a wild one, with the freewill to fend for itself. Although it was now friendly and relying on the human to repair the River, its attitude could easily change. Unless he wanted to kill this one out of hand -- a repugnant choice -- he would have to compromise....

"All right. But we can't waste time."

"Go very fast. Mate and cubs must know, or fear." Splices and their pretensions to humanity! Just what he needed now...

Dos Santos dropped to a crouch in the seatless boat. Trailing a hand in the River, he and the kibe used the time to work up the formula for the denaturing compound that would destroy the toxin. All seemed clear, except -- there were still strings of mysterious purpose in the contaminant....

After some time, the Vortifisher village appeared in a clearing on the upstream bank.

Although the pure silicrobe medium of the upstream third of the River was lifeless, the downstream two-thirds, with its mix of water and 'crobes, supported an entire ecosystem of engineered lifeforms. Near the top of the food chain was the Hyenas' main sustenance, the vortifishes.

The interface between upstream and downstream channels was normally an orderly zone of increasing and decreasing speed gradients, thanks to the programmed interactions of the two types of silicrobes. However, chaotic factors, pattern seeds, occasionally caused whirlpools -- vortices -- of lesser or greater dimensions to butterfly into existence. These were dealt with by the various species of vortifishes, large, powerful, wide-mouthed organisms who derived their sustenance from gobbling the rogue silicrobes (and only the rogues), destroying the vortices in the process.

It took skill and luck and courage for the Hyenas to ride their small boats to the very edge of the vortices and spear their prey, but the cynocephali managed quite superbly -- as they had been engineered to do.

Retreating through layers of shimmerstat windows, Dos Santos focused on the village of podhuts. The bank was thronged with welcoming Hyenas, hunters brandishing their spears, mothers carrying up to four nursing babies in special slings.

Suddenly, the villagers began to scream and gesture, expressions of fear on their faces.

The Hyena throttled down until they stood still. Dos Santos turned to look out to midRiver.

A huge vortice was forming.

"Peej, this is impossible. Silicrobes do not come online by themselves--"

Dos Santos loosened his splatpistol in its holster. "It's happening, though."

Something, some form, was beginning to rise up out of the vortice.

'Fishes nibbled at its base without effect.