David Langford: Different Kinds of Darkness

Jonathan had to ask. 'So the, um, the special kind of dark outdoors is to stop people seeing stuff like that?'

'Well … yes, in effect that's quite right.' The old teacher rubbed his chin for a moment. 'They brief you about all that when you're a little older. It's a bit of a complicated issue…. Ah, another question?'

It was Khalid who had his hand up. With an elaborate lack of interest that struck Jonathan as desperately unconvincing, he said, 'Are all these BLIT things, er, really dangerous, or are there ones that just jolt you a bit?'

Mr Whitcutt looked at him hard for very nearly the length of a beginner's ordeal. Then he turned to the whiteboard with its scrawled triangles. 'Quite. As I was saying, the cosine of an angle is defined…'

The four members of the inner circle had drifted casually together in their special corner of the outdoor play area, by the dirty climbing frame that no one ever used. 'So we're terrorists,' said Julie cheerfully. 'We should give ourselves up to the police.'

'No, our picture's different,' Gary said. 'It doesn't kill people, it…'

A chorus of four voices: '… makes us stronger.'

Jonathan said, 'What do Deep Greens terrorize about? I mean, what don't they like?'

'I think it's biochips,' Khalid said uncertainly. 'Tiny computers for building into people's heads. They say it's unnatural, or something. There was a bit about it in one of those old issues of New Scientist in the lab.'

'Be good for exams,' Jonathan suggested. 'But you can't take calculators into the exam room. «Everyone with a biochip, please leave your head at the door."'

They all laughed, but Jonathan felt a tiny shiver of uncertainty, as though he'd stepped on a stair that wasn't there. 'Biochip' sounded very like something he'd overheard in one of his parents' rare shouting matches. And he was pretty sure he'd heard 'unnatural' too. Please don't let Mum and Dad be tangled up with terrorists , he thought suddenly. But it was too silly. They weren't like that….

'There was something about control systems too,' said Khalid. 'You wouldn't want to be controlled, now.'

As usual, the chatter soon went off in a new direction, or rather an old one: the walls of type-two darkness that the school used to mark off-limits areas like the corridor leading to the old storeroom. The Club were curious about how it worked, and had done some experiments. Some of the things they knew about the dark and had written down were:

Khalid's Visibility Theory , which had been proved by painful experiment. Dark zones were brilliant hiding places when it came to hiding from other kids, but teachers could spot you even through the blackness and tick you off something rotten for being where you shouldn't be. Probably they had some kind of special detector, but no one had ever seen one.

Jonathan's Bus Footnote to Khalid's discovery was simply that the driver of the school bus certainly looked as if he was seeing something through the black windscreen. Of course (this was Gary's idea) the bus might be computer-guided, with the steering wheel turning all by itself and the driver just pretending—but why should he bother?

Julie's Mirror was the weirdest thing of all. Even Julie hadn't believed it could work, but if you stood outside a type-two dark place and held a mirror just inside (so it looked as though your arm was cut off by the black wall), you could shine a torch at the place where you couldn't see the mirror, and the beam would come bouncing back out of the blackness to make a bright spot on your clothes or the wall. As Jonathan pointed out, this was how you could have bright patches of sunlight on the floor of a classroom whose windows all looked out into protecting darkness. It was a kind of dark that light could travel through but eyesight couldn't. None of the Optics textbooks said a word about it.

By now, Harry had had his Club invitation and was counting the minutes to his first meeting on Thursday, two days away. Perhaps he would have some ideas for new experiments when he'd passed his ordeal and joined the Club. Harry was extra good at maths and physics.

'Which makes it sort of interesting,' Gary said. 'If our picture works by maths like those BLIT things … will Harry be able to take it for longer because his brain's built that way? Or will it be harder because it's coming on his own wavelength? Sort of thing?'

The Shudder Club reckoned that, although of course you shouldn't do experiments on people, this was a neat idea that you could argue either side of. And they did.

Thursday came, and after an eternity of history and double physics there was a free period that you were supposed to spend reading or in computer studies. Nobody knew it would be the Shudderers' last initiation, although Julie—who read heaps of fantasy novels—insisted later that she'd felt all doom-laden and could sense a powerful reek of wrongness. Julie tended to say things like that.

The session in the musty storeroom began pretty well, with Khalid reaching his twenty seconds at last, Jonathan sailing beyond the count of ten which only a few weeks ago had felt like an impossible Everest, and (to carefully muted clapping) Heather finally becoming a full member of the Club. Then the trouble began, as Harry the first-timer adjusted his little round glasses, set his shoulders, opened the tatty ritual ring-binder, and went rigid. Not twitchy or shuddery, but stiff. He made horrible grunts and pig-squeals, and fell sideways. Blood trickled from his mouth.

'He's bitten his tongue,' said Heather. 'Oh lord, what's first aid for biting your tongue?'

At this point the storeroom door opened and Mr Whitcutt came in. He looked older and sadder. 'I might have known it would be like this.' Suddenly he turned his eyes sideways and shaded them with one hand, as though blinded by strong light. 'Cover it up. Shut your eyes, Patel, don't look at it, and just cover that damned thing up.'

Khalid did as he was told. They helped Harry to his feet: he kept saying 'Sorry, sorry,' in a thick voice, and dribbling like a vampire with awful table manners. The long march through the uncarpeted, echoey corridors to the school's little sickroom, and then onward to the Principal's office, seemed to go on for endless grim hours.

Ms Fortmayne the Principal was an iron-grey woman who according to school rumours was kind to animals but could reduce any pupil to ashes with a few sharp sentences—a kind of human BLIT. She looked across her desk at the Shudder Club for one eternity of a moment, and said sharply: 'Whose idea was it?'

Khalid slowly put up a brown hand, but no higher than his shoulder. Jonathan remembered the Three Musketeers's motto, One for all and all for one , and said, 'It was all of us really.' So Julie added, 'That's right.'

'I really don't know,' said the Principal, tapping the closed ring-binder that lay in front of her. 'The single most insidious weapon on Earth—the information-war equivalent of a neutron bomb—and you were playing with it. I don't often say that words fail me …'

'Someone left it in the photocopier. Here. Downstairs,' Khalid pointed out.

'Yes. Mistakes do happen.' Her face softened a little. 'And I'm getting carried away, because we do actually use that BLIT image as part of a little talk I have with older children when they're about to leave school. They're exposed to it for just two seconds, with proper medical supervision. Its nickname is the Trembler, and some countries use big posters of it for riot control—but not Britain or America, naturally. Of course you couldn't have known that Harry Steen is a borderline epileptic or that the Trembler would give him a fit….'

'I should have guessed sooner,' said Mr Whitcutt's voice from behind the Club. 'Young Patel blew the gaff by asking what was either a very intelligent question or a very incriminating one. But I'm an old fool who never got used to the idea of a school being a terrorist target.'