The testing of my prototype Nano-detector was going as well as could be expected: I was actually finding software bugs in the various subsystems I had assembled which evidently prevented the whole thing from working. Still, I kept plugging away, until came the day which I could try a live end-to-end test. I loaded the most recent version of the detector app into the old phone I was using as a test rig, and fired it up; there was a pause while my software initialised the signal processing chip to start listening, then a beep and a green indicator on the screen suggesting that the device was actively searching the airwaves.

I then started the by-now boringly familiar process of trying to build a nano-device of my own, which would always facilitate the appearance of a Nano-suppressor. My vacuum chamber is of course a solid piece of medical grade stainless steel, so it is also an effective Faraday cage for screening radio signals of all kinds. But it also had a couple of quartz glass observation ports - in practice, holes in the screening - through which I should be able to detect radio activity.

I ran the process to the point of provoking an appearance, then turned off my equipment and turned on the spectrum analyser, then held my old phone to one of the glass ports. The phone screen lit up, displaying the characteristic radio signatures in time with the spectrum analyser, and emitting the familiar chuff, chuff noises.

My other phone pinged; the one which still functioned as a proper phone. I had forgotten the Bluetooth link to my other phone, but even that seemed to be working; I had a message informing me that a Nano-suppressor had been detected. The signals detected decreased sharply and then disappeared entirely, presumably as the Nano-suppressor finished eating my creation and then destroyed itself. All-in-all, a successful test.

I repeated my tests several times that afternoon, all of which suggested my app was working at least adequately, although I made copious notes on possible additional functions and usability improvements at the user interface, which was presently pretty clunky, I admit. For the last test, I even repressurised and opened the vacuum chamber entirely - an expensive operation since it would take hours to re-purge and evacuate the chamber for future use - which allowed me to get an initial idea of the range of the Nano-suppressor detector. This was quite interesting, indeed gratifying, since it suggested the range might well be greater than the dimensions of my laboratory.

So, I was feeling extremely positive and, only slightly, smugly pleased with myself when I left the lab that evening. Without really thinking about it, I put both phones in my pocket when leaving to take a shower and change my clothes; carrying around mobile communications devices is an instinct which we humans have grown familiar with over the decades.

I was going out to meet Maeve for dinner and, later on, yes, sex this evening; again, I put both phones in my pocket more or less on autopilot, perhaps subconsciously expecting to show off later on. As it was, I must have decided that showing my girlfriend a nerdy gadget project, even one as technically literate as Maeve, was probably a step in the wrong direction and, in any case, our conversations rapidly explored other topics, as they often did.

Over a glass of wine, Maeve asked: "how long do you suppose have these aliens, these Gods been interfering in human activity?"

I thought for a moment; I had found it was always worth giving serious consideration to any question the Professor asked.

"Since the middle of the twentieth century," I suggested eventually, "Actively slowing down the development of spaceflight after the first moon landings."

"I agree that might well have been one of their actions," she agreed, "But perhaps they have been having indirect influence for much longer. Look at that long period called the Dark Ages in Europe, a period of perhaps a thousand years where little or no technical advancement was made."

"While Hawaii, for example, was managing fairly intensive farming," I interjected, "Like much of the rest of the world."

"Indeed so," she agreed, "Perhaps their influence goes right the way back into pre-history. The European enlightenment, and the scientific and industrial revolutions represented a failure, for them."

I could not disagree with her reasoning although, at the time, I was unsure why our conversations kept veering onto this topic. The evening flew by, soon reaching the the ritual 'your place or mine?' line, which had become something of a private joke between us, given that the little rooms - cells might be a more apt word - provided by the facility were substantially identical. We elected for 'my place'.

The following morning, after Maeve had left, I pottered about my room with a dumb smile on my face, showering and dressing and generally tidying up. I found the two phones still in my trouser pocket; idly I unlocked the one I had modified and was startled to be confronted by hundreds, thousands of alerts. Nano-suppressors had been extremely active in my room all night; not just one or two, but a great many, some with signatures different from the ones I had encountered in my lab, but still within the detection tolerances I had built into my software.

The alerts had stopped now; nothing was being detected. But when I looked at the records, it seemed that the cessation of nanotechnology activity corresponded exactly with Maeve leaving my room. I was forced to the conclusion that her body was infested with millions of the devices, judging by the strength of the signals my device had picked up.

I sat on the edge of the bed for a few minutes, thinking. I could not imagine a reason why Maeve's body should harbour so many nanodevices, although of course I could not know if other people were similarly infected. But it did occur to me that I might be able to use the equipment in my lab to image these devices; there must be some left behind. A forensic analysis would immediately reveal that Maeve had been in my room, and it was easy enough for me to collect some of the more obvious samples: a long hair here, a paper handkerchief there.

I hurried off to the lab and prepared the samples as best I could, then fixed the mount inside the vacuum chamber. I waited impatiently as the pumps clattered away sucking the last vestiges of atmosphere from within. Finally, I could fire up the scanning electron microscope, set the scanning resolution - effectively, magnification - to a wide setting and scrolled up and down until I found Maeve's hair.

Part 3 Part 5