Its computers triangulating the object's line of movement to project its likely path of retreat, the hedgehog gave chase, slinging across the rocky soil on its all-terrain carrier.

Suddenly another source of human IR emissions appeared, this one behind the hedgehog.

Then a third on its right, and a fourth on the left.

The robot stopped again, boxed in. Its various turret sensors needed just an instant to perform a sweep extending for fifty meters in a full circle. At the same time, its infrared illuminator was casting a light field that enabled its night video equipment to scan for images in the pitch darkness.

Again the four anomalous radiation sources dashed into and out of range, still surrounding the robot, their pattern of motion keeping them roughly equidistant from it.

Its logical systems correlating the input from its probes, the hedgehog had definitively classified the circling objects as human entities and potential threats. But very much by design, its programming did not include any options for dealing with them.

Instead, it was transmitting the processed data to its monitoring site via an encrypted radio channel, leaving its flesh-and-blood handlers to decide what to do next.

"What's up with Wally?" Jezoirski said. "You see how he's sniffing around?"

"Yeah," Delure replied with concern. "And I don't like it a bit."

Beside them, Cody, the senior man in the room, leaned pensively over his surveillance monitors and said nothing.

At their monitoring station in the bowels of the Brazilian ISS compound, the guards were studying a complex bank of dials, controls, and electronic displays that placed them at the informational heart of its security network. All three wore the indigo uniforms and newly issued shoulder patches--these depicting a broadsword surrounded by stylized satellite bandwidth lines--of UpLink's global intelligence and threat countermeasure force, dubbed Sword as a reference to the legend of the Gordian knot, which Alexander the Great was supposed to have undone with a swift and decisive stroke of his blade. It was a method analogous to Roger Gordian's no-nonsense approach to crisis management, making for some interesting word play, and forming the direct basis of the section name.

Jezoirski slid forward in his chair, his features limned by the pale green radiance of an infrared video display, his eyes on the IR meter directly beneath it.

"Shit," he said. "Look at that heat emission. Somebody's definitely out th--"

Jezoirski broke off midsentence as a warning indicator lit up on the panel. He glanced over at Delure, who took hurried note of this development and then pointed back at the video screen.

Green-on-green images flashed across the monitor--a group of human figures moving around the security robot, alternately closing in and backing away.

Cody thought of bloodhounds harrying their prey. But why would those sons of bitches play tag with the 'hog? The robots' main effectiveness lay in their early alert and standoff capabilities against a perimeter attack. Their purpose was to buy time until human reinforcements arrived, to repel or delay an intrusion attempt while it was in progress. Their purpose was not to engage in close skirmishing once the grounds were already compromised. At that stage getting past them would be easy, and crippling or taking them out just slightly more difficult.