So, then, the doctor confronts Interface Three, through which he daily enters the residential suite of his master the Khan. It is a ponderous diamond-shaped doorway, two and a half meters high. From its silken-smooth bronze surface jut a dozen and a half warty cylindrical snouts, three to nine centimeters high. Some of them are scanners and sensors, some are audio conduits, some are weapons of ineluctable lethality; and Shadrach Mordecai has no idea which is which. Most likely, what serves as a scanner today may well be a laser cannon tomorrow; with such random shifts of function does Genghis Mao contrive to confuse the faceless assassins he so vividly dreads.

“Shadrach Mordecai to serve the Khan,” Mordecai says in a clear firm voice into what he hopes is today’s audio pickup.

Interface Three, now emitting a gentle hum, subjects Mordecai’s announcement to voiceprint analysis. At the same time, Mordecai’s body is being checked for thermal output, mass, postural stress, olfactory texture, and much more. If any datum should fall beyond the established Mordecai-norm, he could find himself immobilized by loops of suddenly spurting webfoam while the guards are summoned to investigate; resistance at that point might lead to his immediate destruction. Five of these interfaces protect the five entrances to Chairman Genghis Mao’s chambers, and they are the wiliest doors ever devised. Daedalus himself could not have forged more clever barriers to guard King Minos.

In a microsecond Mordecai is recognized to be himself, rather than some cunning lifelike simulacrum on a king-slaying errand. With a smooth hiss of perfectly machined joints and a gentle nimble of flawless bearings the interface’s outer slab glides open. This admits the doctor to a stone-walled inner holding chamber hardly larger than himself. No welcome vestibule for claustrophobes, this. Here he must halt another microsecond while the entire surveillance is repeated, and only after he passes this second muster is he allowed to enter the imperial residence proper.