"It was designated 88-0009-ATY, but in the files it's also referred to as Oul's Egg, or simply 'the Egg'. Technically it wasn't egg-shaped, but an ellipsoid, a three-dimensional oval. One point eight nine eight eight metres along the long axis, circular cross-section expanding to zero point seven three four zero metres at its widest point. About the size of a man. Mirror finish. Completely silent, completely inert. No measurable temperature, no noise or vibration from within, no electromagnetic emissions, no movement.

"You could reach your hand into it. If you were wearing a ring or a watch they'd get stopped. A subcutaneous implant, also stopped. But your hand would pass through fine. Your shirt sleeve would be bunched up against the exterior shell while your arm went all the way in. But nothing else. Knives couldn't damage the shell. Scalpels, no. Drills, no. Bullets, no. Cutting lasers, no. An extremely expensive industrial hydraulic press was destroyed trying to make it crack under force.

"The lasers were an interesting test. The laser light was all reflected. And I mean all of it. All light falling on the shell was reflected. That's thermodynamically impossible for a mirrored surface. All mirrors are imperfect. This one wasn't. The same happened when the Egg was tested with thermal radiation, microwaves, ultraviolet, gamma rays, X-rays, radio waves... which meant that there was no way to scan the Egg's interior. Except by reaching inside it and feeling around.

"This was done.

"Volunteers had to be brave. There could have been machinery, chemical reactants, sharp edged blades moving at high speed, anything. Obviously the volunteers couldn't wear protective clothing; the gloves couldn't go through, only their bare hands. But a systematic search of the Egg's whole interior found nothing. It was reported that the Egg felt warm inside; in fact, a hand put into it rapidly began to overheat. It turned out this was the volunteers' own body heat, unable to escape, because it was being reflected back on their hands by the shell. The Egg itself had no measurable temperature.

"Living human flesh could penetrate the Egg. Portions of your body which would be considered "dead" could too: toenails, the top layer of skin, body hair, tooth enamel. Blood could. Blood dripped out of an open wound on somebody's arm could. Fingernail clippings, fine.

"Air couldn't pass through the Egg. Including air held in a volunteer's mouth, nose or lungs. As a result, a volunteer couldn't climb into the Egg without rupturing their lungs, and this was not attempted. Fillings in teeth couldn't pass through. Contact lenses couldn't pass through. The rest of a human head could, with no problems, although the experience was profoundly unpleasant, something akin to live burial.

"Now the obvious question at this point in the briefing is why all these tests were performed on live humans, instead of animals, namely lab rats.

"Lab rats couldn't penetrate the Egg.

"Wood couldn't penetrate the Egg. Inorganic matter, no. Metal, no. Dead vegetable matter, no. Live plants, no. Live rats, no. Live mice, no. Dead animal flesh - meat - no. Living higher animals, no. Dogs, no. Apes - a female ape was obtained to experiment on, she was returned unharmed - no. But humans, yes.

"Living humans, yes. Living human flesh, yes. Dead human flesh, no. Or so it seemed at first. A severed human hand, no. A skull, no. Preserved organs, no. But then it was found that surgically removed human organs would pass through with no problem. Which was initially confusing. But then a pattern was discovered: permeability depended on the alive-or-dead state of the originating human of the body part in question. A body part of a living human? Yes. A body part from a dead human? No.

"Some ethical debate followed.

"Several convicted prisoners who had been given the death penalty were approached. Several of those approached expressed an interest in furthering the cause of science, in exchange for a relatively swift timetable and a relatively peaceful execution. One man was selected. A great deal of bureaucractic and legal documentation was processed. The man was transported to the experiment laboratory at Tarczal Mountain. The first forty centimetres of his arm were inserted into the centre of the ellipsoid, and he was made to breathe air mixed with increasing amounts of carbon monoxide, inducing sleep, suffocation and finally death. This experiment was scheduled to begin at 14:00 hours, local time, 1st July 1988.

"From this point onwards there is a four-day gap in the official record."

*

"At around midday on 5th July, following two consecutive missed scheduled communiques by the Tarczal lab's Operations Commander, a party of armed investigators arrived by truck at Tarczal's ground level entrance. Here, it was discovered that the facility's Emergency Black Site Containment system had been manually triggered, flooding the personnel elevator shaft, freight elevator shaft, emergency stairwells and camouflaged vent shafts with a layer of cement eight feet thick.

"The idea behind the EBSC - versions of which are still in use to this day though none have ever been activated - is to protect the outside world when something goes catastrophically wrong at a black laboratory site. The canonical example is a contagious biological hazard or a radioactive hazard. It protects the world from whatever may have been spilled, and it protects the world from knowing that the black laboratory existed in the first place.

"Given that there were never any dangerous biological or viral substances present on the site, the investigators surmised that there had been a leak in the Tarczal laboratory's nuclear generator, and the Operations Commander had bravely sacrificed himself and his subordinates to contain that leak, rather than risk another disaster on the scale of Chernobyl.

"Thirty-eight people were killed.

"The incident was covered up. This was not difficult; all of the thirty-eight on the black site had airtight cover stories already in place. The project was abandoned and the site sealed off. The matter was forgotten until forty-eight hours ago."

*

"There was no leak."