She staggers after him a little way, but stops again. She is losing the signal. When he is thirty yards away, she slides once more into her dormant state.
All of this is good news. It is consistent with how the camouflage suit is meant to work.
As soon as the hungries’ heat-seeking ability became verified fact, Greaves began to study it. He tried in dissections to identify the organs or structures involved, but there is no single front-runner. He has established that the visual cortex of a human brain undergoes extensive changes shortly after the onset of infection, which suggests that the pathogen may heighten visual acuity in the infra-red range. It’s equally plausible, though, that the passive thermoreceptor cells at the base of the tongue have been co-opted for this purpose (which would explain why hungries gape their mouths when they hunt).
At a certain point, he put this question on the back burner and switched his attention to counter-measures. Whatever the precise mechanism of heat detection may be, in order to confuse it all you need to do is to smear or block your heat emissions in some way. Blocking is problematic. It leaves you the problem of what to do with stored heat, which if it can’t be vented will kill you as surely as the hungries will. So he decided to go with camouflage.
Before the Breakdown, the Israeli army were trialling a heat-signature camouflage system which they christened Adaptiv. Even in its prototype form it was able to make a tank look like a car or a flat-bed truck to thermal scanning systems, or to make it invisible against background ambient temperature. The secret was a layer of flat tiles on the vehicle’s surface which could be separately heated and cooled, effectively providing a coat of many colours in the infra-red.
Inspired by Adaptiv, Greaves has produced an actual coat of no colours at all. He used whatever was available—scraps he had scavenged up from Rina’s lab and brought with him, materials laid in for Rosie’s repair and maintenance, serendipitous finds from stops along their journey—and stored the work-in-progress in one of the freezer compartments intended for whole cadavers. There are ten of these compartments and only seven of them have been filled.
The heat-suit covers his body like a second skin. Its exterior surface is dotted here and there with modified cats’ eye studs—like the Adaptiv tiles but three-dimensional—which focus and channel heat rather than light. The visual effect is grotesque in the extreme, like a diving suit designed by a sexual fetishist, but in theory the suit will broaden and flatten his heat signature and even create hotspots in the air around him. It’s like throwing your voice, but what you’re throwing is your energy, the exhaust from your ever-working metabolism. Instead of a single source of heat from which the hungries can take a range and a direction, he’s the centre of an ever-changing thermal disturbance. The effect he is hoping for is confusion: if the hungries can’t track him consistently from one moment to the next, perhaps their tropism—their heat-seeking mechanism—will fail to engage. Based on the available evidence so far, the theory is holding.
There’s a downside, though. The suit does, after all, store heat. The radiant vents work reasonably well when he is still, but now that he is walking he can feel his core temperature climbing up. It’s a serious problem. He wishes he had installed a temperature read-out of some kind, an LED thermometer in one of the suit’s sleeves. It would be useful to know whether he is actually in danger of heat prostration, or close to it. Subjectively, he feels uncomfortable but not weak or dizzy or sick. He judges that he will reach Invercrae before any critical thresholds are passed.
He crosses the Telford bridge over the River Moriston, a tourist attraction in former times. The roar of the falls above the town makes him pause for a second, afraid for no definable reason. He steels himself, annoyed at the irrational response, and walks on into the town.
Although to call it that seems like comical exaggeration. It’s a main avenue and a square, with a few short, blunt side streets, most of which end at the river. Even before the Breakdown, it could never have had more than five hundred inhabitants. Now a few hungries stand at street corners as though they’re waiting for someone to come and lead them back into the lives they lost.
They will stand like this until their body’s systems fail, barring occasional headlong sprints in pursuit of local fauna. It’s an afterlife that not even the grimmest and least user-friendly of the old world’s religions ever imagined.
Greaves walks along the main street, his pace a controlled and inconspicuous amble. He is careful to keep his distance from the hungries. The scatter effect of his heat-suit will be aided and abetted at wider distances by the inverse square rule, and ought to be enough to protect him. At close quarters, he may still become a focus. Again and again, the nearest hungries react like the woman on the road did. They jerk into life as Greaves goes by, dance on the spot for a few moments but fail to translate their agitation into forward motion.
But the heat and discomfort are becoming more acute. He has to stop exerting himself and allow his body to cool down naturally as his metabolism slows. This will take more time than it would if any part of his skin were open to the air. But he has sweated heavily inside the suit, almost certainly undoing the masking effect of the e-blocker gel. Taking any part of the suit off now is impossible.
He finds a café whose windows have been folded back, years before, to open its frontage entirely to the street. It stands at the top of a steep rise, a vantage point from which most of the town is visible. Back before the world ended, this must have been an attractive spot to sit and watch some tiny fraction of it go by. Greaves steps in off the street and finds a place to stand, in shadow and—he hopes—safe from detection. He doesn’t try to sit: the suit is too rigid to allow him to do that in comfort, and once down he would not be able to get up again quickly.
His immediate problems aside, the primary goal of this sortie remains unchanged. From here he can see nine hungries, four males and five females. He will observe them for as long as he can, and take mental notes on their nocturnal behaviours.
And the girl? He has no idea, no clue as to where she might be. Unless she walks across his field of vision he will be forced to seek her out. Slowly. Very slowly. If the suit fails, his situation will become untenable.