“Yes, sir.” Dr Stephenson collected her thoughts. “I was already thinking about nanoshells when I heard about the gold particles, but Alex has made it all clear. It’s quite complicated and I know we don’t have a lot of time, but I’ll try to make it as simple as I can.
“Injections must be the answer. What these people have done is to inject first the football players and then goodness knows how many children with gold-coated nanoshells.” She paused. “What we’re talking about here are tiny bullets—and by tiny I mean about a hundred nanometres across. Just so you know, one nanometre is a billionth of a metre. Or to put it another way, a single hair on your head is about one hundred thousand nanometres wide.
So each one of these bullets is a thousand times smaller than the tip of a human hair.” She leant forward, resting her hands on the table. Nobody moved. Alex couldn’t hear anyone so much as breathe.
“What might these bullets consist of?” Dr Stephenson continued. “Well, it’s anyone’s guess. But if you imagine a Malteser, it would be a bit like that.
The inside would be what we call a polymer bead and might be made of something not very different to a supermarket carrier bag. Don’t forget, though, I’m only talking about a few molecules. The polymer would hold everything together and it would be quite easy to mix in the cyanide. When the polymer and the cyanide are released, the person dies.
“And what stops it being released? Well, that’s the chocolate on the outside of the Malteser—except what we’re talking about here is gold. A solid gold shell, but so tiny you could never see it. All of this would have been done by Dr Liebermann, the man who was killed, using highly advanced colloidal chemistry.” She stopped again. “I’m sorry. I’m probably making it sound more complicated than it really is. Basically, what you’ve got is a bullet with the poison inside, and after that you fix a protein onto the outside, onto the shell.”
“What does the protein do?” someone asked. “It guides the whole thing, a bit like a heat-seeking missile. It would take too long to explain how it works, but proteins can find their way around the human body. They know exactly where to go. And once the nanoshell was injected, the right protein would direct it straight to the heart.”
“How many of these nanoshells would you need to inject?” Blunt asked.
“That’s impossible to answer,” Dr Stephenson replied. “They’d be sitting right inside the heart. Once the poison was released, it would act almost immediately and you wouldn’t need very much of it. As a matter of fact, we’ve studied the effect of nanoshells on the human body, developing them as a cure for cancer. Of course, this is rather different because Scorpia are only interested in killing, but let me see…” She thought for a moment.
“There’s not very much liquid in a BCG injection. Only about a fiftieth of a teaspoon. At a guess, I’d say you’d only need to add one part cyanide for every one hundred parts of the actual vaccine.” She worked it out and nodded. “That adds up to about one billion nanoshells,” she said. “Just enough to cover the head of a pin.”
“But you said that the poison is safe. It’s protected by the gold.”
“Yes. But I’m afraid that’s where these people have been so very clever. The polymer and poison mix is contained in the gold. It’s sitting inside the heart and it’s not doing anyone any harm. If you leave it alone, it’ll just pass out of the system in a little while and nobody will be any the wiser.
“But Scorpia can break up the gold. And they can do it, like Alex said, by remote control. Have you ever put an egg in a microwave? After a few moments, it explodes. It’s exactly the same here. It could be microwave technology that they’re planning to use.” Stephenson shook her head, her long hair swaying. “No. Microwaves would be too low frequency. I’m sorry. I’m not really an expert on plasmon resonance.” She hesitated. “A terahertz beam might be the answer.”
“I’m sorry, Dr Stephenson,” the foreign secretary said, “but you’re losing me. What are terahertz beams?”
“They’re not much used yet. They sit between the infrared and the microwave bands of the electromagnetic spectrum and they’re being developed for medical imaging and satellite communications.”
“So you’re saying that Scorpia could send out a signal using a satellite and it would break up the gold, releasing the poison…”
“Yes, sir. Except they wouldn’t actually need to use a satellite. In fact, they couldn’t. The beams wouldn’t be strong enough. If you ask me, when those poor men got off the plane at Heathrow, there must have been some sort of satellite dish erected. It was probably put there a long time ago, on one of the buildings or perhaps up a mast, and they’ll have taken it down by now. But all they had to do was throw a switch, the terahertz beams would have broken down the gold and … well, you know the result.”
“Is there any chance that the nanoshells could be broken up accidentally?” Sir Graham Adair asked.
“No. That’s what’s so brilliant about the whole thing. You’d need to know the exact thickness of the gold. That tells you what frequency to use. It’s just like when you shatter a glass by singing the right note. If you ask me, Alex saw that same technology at work with that tiger. The animal must have had some sort of sedative in its bloodstream. They just had to press a button and it fell asleep.”
“So if they’re not using a satellite, what are we looking for?”
“A saucer. It would look much the same as a satellite TV dish, only bigger. They’ve said they’re targeting London kids, so it will have to be somewhere in London. Probably mounted on the side of an office building.
They may call it Invisible Sword, but I’d say it’s more like invisible arrows being fired out of satellite dishes.
They shoot out in a straight line.”
“And how long will it take for the gold to break up once the switch is thrown?”
“A few minutes. Maybe less. Once the gold breaks, the children will die.” Dr Stephenson backed away from the table and sat down again. She had nothing more to say. Immediately everyone began to speak at once. Alex noticed some of the civil servants talking into mobile phones. The two women in black and white were typing furiously, trying to keep up with the babble of conversation. Meanwhile, the permanent secretary had leant across Alex, talking quickly and quietly to Alan Blunt. Alex saw the spy chief nod. Then the prime minister held up a hand for silence.
It took a few moments for the clamour to die down.
The prime minister glanced at his director of communications, who was looking down, biting his nails.
Everyone was waiting for him to speak.
