The computer simulation showed the information being broadcast from Haven to the metal-encased probe. Above ground, cartoon human scientists scratched their heads and tore up their notes.
‘Most amusing,’ said Artemis.
Butler was studying the hologram. ‘I’ve been on enough campaigns to know that there is a big hole in that strategy, Artemis,’ he said.
‘Yes?’
Butler struggled to his knees, tracing the probe’s path with a finger. ‘Well, what if the probe’s journey brought it into contact with one of the People’s chutes? Once that metal punctures a chute, it’s on an express ride to Haven.’
Artemis was delighted at his bodyguard’s astuteness. ‘Yes, of course. Which is why there is a supersonic attack shuttle on standby twenty-four hours a day, to divert the molten mass if the need should arise. All human probe projects are monitored, and if any are judged to pose a threat they are quietly sabotaged. If that doesn’t work, the LEP geological unit drill in under the molten mass and divert it with some shaped charges. The orebody follows the new path blown for it, and Haven is safe. Of course, the mining shuttle has never been used.’
‘There’s another problem,’ added Holly. ‘We have to factor in Opal’s involvement. She has obviously helped Giovanni Zito drill through the crust, possibly with a fairy laser. We can presume that she has upgraded the probe itself, so that
Foaly’s false signals will not be accepted. So her plan must be to bring that probe into contact with the People. But how?’
Artemis launched a third holographic animation, shutting down the first two. This three-dimensional rendering portrayed Zito’s Earth Farm and the underlying crust and mantle.
‘This is what I think,’ he said. ‘Zito, with Opal’s help, liquefies his orebody here. It begins to sink at a rate of five metres per second towards the Earth’s core, taking accurate readings, thanks to Koboi’s upgrades. Meanwhile, Foaly thinks his plan is working perfectly. Now, at a depth of one hundred and six miles, the metal mass comes within three miles of this major chute, E7, which emerges in southern Italy. They run parallel for a hundred and eighty-six miles, then diverge again. If Opal were to blow a crack between these two tunnels, then the iron would follow the path of least resistance and flow into the chute.’
Holly felt the strength leave her limbs. ‘Into the chute, and straight down to Haven.’
‘Exactly,’ said Artemis. ‘This particular chute runs in a jagged westerly diagonal for twelve hundred miles, coming within five hundred metres of the city itself. With the speed the orebody will build up in freefall, it will slice off a good half of the city. Everything that’s left will be broadcasting signals for the world to hear.’
‘But we have blast walls,’ objected Holly.
Artemis shrugged. ‘Holly, there isn’t a force on Earth or under it powerful enough to stop a hundred million tonnes of molten haematite in freefall. Anything that gets in the way will be obliterated. Most of the iron will curve round and follow the tunnel, but enough will continue straight down to cut right through the blast walls.’
The shuttle’s occupants watched Artemis’s computer simulation in which the molten orebody smashed through Haven City’s defences, allowing all the fairy electronic signals to be picked up by the probe.
‘We are looking at a fifty-eight per cent casualty rate,’ said Artemis. ‘Possibly more.’
‘How can Opal do this without Foaly’s sensors picking her up?’
‘Simple,’ replied Artemis. ‘She simply plants a shaped charge in E7 at a depth of one hundred and six miles, detonating it at the last minute. That way, by the time Foaly detects the explosion it will be too late to either disarm it or do anything about it.’
‘So we need to remove that charge.’
Artemis smiled. If only it were that simple. ‘Opal will not take any chances with the charge. If she left it on the chute wall for any amount of time, a tremor could shake it free or one of Foaly’s sensors could pick it up. I’m sure the device is well shielded, but one leak in the plating could have it broadcasting like a satellite. No, Opal will not position the charge until the last minute.’
Holly nodded. ‘OK. So we wait until she plants it, then we disarm it.’
‘No. If we wait in the chute, then Foaly will pick us up. If that happens, Opal will not even venture down the chute.’
‘That’s good, isn’t it?’
‘Not really. We may delay her for a few hours, but remember Opal has a hundred and eighty-six mile window to plant the charge. She can wait for the LEP to arrest us and still have ample time to complete her mission.’
Holly knuckled her eyes. ‘I don’t understand this. Surely everyone must know by now that Opal has escaped. Surely Foaly can put this all together.’
Artemis closed his fist. ‘There’s the rub. That single point is the essence of this entire situation. Foaly obviously doesn’t know that Opal has escaped. She would be the first person checked after the goblin general’s escape.’
‘She was checked. I was there. When Scalene escaped, Opal was still catatonic.
There’s no way she could have planned it.’
‘And yet she did,’ mused Artemis. ‘Could that Opal have been a double?’
‘Not possible. They run DNA checks every day.’
‘So the Opal under surveillance had Koboi’s DNA, but little or no brain activity.’
‘Exactly. She’s been that way for a year.’
Artemis thought silently for over a minute. ‘I wonder how far cloning technology has developed underground?’
He crossed briskly to the main computer terminal, calling up LEP files on the subject.
‘The mature clone is identical to the original in every way, except that its brain functions are limited to life support,’ he read. ‘In greenhouse conditions, it takes one to two years to grow a clone to adulthood.’ Artemis stepped away from the computer, clapping his hands. ‘That’s it. That’s how she did it. She induced that coma so that her replacement would not be noticed. This is impressive stuff.’
Holly pounded a fist into her palm. ‘So even if we did survive the attempts on our lives, all talk of Opal’s escape would be seen as the ravings of the guilty.’
‘I told Chix Verbil that Opal was back,’ said Mulch. ‘That’s OK, though, because he already thinks I’m raving.’
‘With Opal on the loose,’ continued the Irish youth, ‘the entire LEP would be on the lookout for a plot of some kind. But with Opal still deep in her coma…’
‘There is no cause for alarm. And this probe is simply a surprise, not an emergency.’
Artemis shut down the holographic projection. ‘So, we’re on our own. We need to steal that final charge and detonate it harmlessly above the parallel stretch. Not only that, but we need to expose Opal so she cannot simply put her plan into action all over again. Obviously, to do this we need to find Opal’s shuttle.’
Mulch was suddenly uncomfortable. ‘You’re going after Koboi? Again? Well, best of luck. You can just drop me off at the next corner.’
Holly ignored him. ‘How long do we have?’
There was a calculator on the plasma screen, but Artemis didn’t need it. ‘The orebody is sinking at a rate of five metres per second. That’s eleven miles per hour. At that speed it would take approximately nine and a half hours to reach the parallel stretch.’
‘Nine hours from now?’
‘No,’ Artemis corrected her. ‘Nine hours from detonation, which was almost two hours ago.’
Holly walked rapidly into the cockpit, strapping herself into the pilot’s chair.
‘Seven and a half hours to save the world. Isn’t there some law that says we get at least twenty-four?’
Artemis strapped himself into the co-pilot’s chair. ‘I don’t think Opal bothers with laws,’ he said. ‘Now. Can you talk while you fly? There are a few things I need to know about shuttles and charges.’
Chapter 10: Horse Sense
