“Isn’t that Dr. Parks?”

He called Parks over, and the lecturer moved through the crowd that was rapidly forming for no other reason than that there was a crowd forming.

“Hullo, Inspector,” said Parks, panting slightly. “I got here like you asked.”

“I didn’t ask you,” replied Jack with a frown, “but no matter—got something for us?”

“And how!” He looked around curiously at the milling crowd.

“What’s the ruckus?”

“Bartholomew’s holed up in there with a sloth of bears.”

“Ah! Well, check this out,” Parks said excitedly, handing them several photomicrographs from the scanning electron microscope.

“We had to search around, but we finally got there,” he said triumphantly, tapping the image. “How did you know?”

“Call it a hunch. I’d like you to get this on the Conspiracy Theorist Web site as soon as you can; spread it around so everyone knows. Okay?”

“Sure.”

“I see it,” said Mary, still staring at the pictures, “but what does it mean?”

“It means Bisky-Batt lied to us—I thought all that smarmy ‘In what way can I assist you, Officer?’ rubbish was too good to be true.”

There was a loud siren from close by, and an armored car drove up, parked and disgorged a dozen more troops, all heavily armed. It was turning into an all-out siege.

“There’s something else,” said Parks.

“Yes?”

“I was thinking again about the Nullarbor blast, and something stirred in my memory. I had a look through some back issues of Conspiracy Theorist and discovered that there is a theory that might explain the sort of damage we saw at Obscurity and on the Nullarbor. It was first postulated in the 1950s but was so far-fetched that even the hard-core pseudoscience elite dismissed it as nonsense. It was called Cold Ignition Fusion and was a way of building a small thermonuclear device using a deuterium/tritium fuel that could be self-extracting from the heavy hydrogen found in groundwater, and then a mass-induced organic trigger to set it off. It’s on a par with the moon being made of green cheese and the existence of a Mayan temple under Cleethorpes, but the result would be pretty much what we saw at Obscurity and all the others. A small thermonuclear blast in the region of a half to one kiloton.”

“Cold Ignition Fusion?” queried Jack. “Just how impossible is it?”

“In the current climate of scientific thought, it’s in frilly bonkers la-la land, but great minds have been wrong before. In 1933, Ernest Rutherford declared that the vast energies in the atomic nucleus could never be unlocked and that anyone who said otherwise was talking utter moonshine. An undisputed genius, Inspector, yet quite wrong on this occasion. Cold Ignition Fusion is perhaps not impossible but highly, highly improbable—and believe me, my mind is broad.”

“But if it could be done?” asked Mary.

“Hypothetically?” asked Parks.

“Hypothetically.”

“If it could be done,” he said with a smile, “can you imagine the value of such a discovery? Unlimited safe and cheap power from water. Truly, lightning in a bottle.”

“But on the other side of the coin,” said Mary, “bargain-basement nuclear weapons.”

A cold shiver ran down Jack’s spine as events suddenly popped into sharp focus.

“Shit,” he said, “I’ve been an idiot. Quickly: Using Cold Ignition, how much mass would a device have to reach before self-ignition would begin?”

“Almost exactly fifty kilos. The theory is suspect, but quite precise.”

Jack turned to Ashley. “Ash, I just hope your total recall is as good as you say. I need the weight of Cripps’s champion cucumber the last time he reported to Fuchsia.”

“110001 point 1010111.”

“That’s 49.87 kilos—Katzenberg’s?

“110001 point 1100000.”

“Okay, 49.96. What about Prong’s?”

“110001 point 1011001.”

“Still mighty close—49.89.”

“You’re right,” said Ashley. “There is a connection. Fuchsia’s was 110001 point 1001010; there’s barely one percent difference between them all.”

Jack thumped his fist into his palm. “All a few grams under the magic fifty kilos. I’ve been looking at this ass-about-face. People didn’t blow up those cucumbers. Those cucumbers blew up the people. The champions reach fifty kilos, hit critical mass and—boom.”

“What?” exclaimed Parks, who despite being a leading light in the pseudoscience movement was having serious trouble over this. “Come on, doesn’t that seem a bit improbable?”

“Improbable is standard working procedure within the NCD,” replied Jack grimly. “Cripps, Katzenberg, Prong and Fuchsia just thought they were growing heavy cucumbers, but McGuffin, flitting around with his Men in Green in the background, was changing, crossbreeding, bioengineering and reseeding until he had created a devastatingly destructive power that could be created in a grow bag with nothing more complex than a dibbler and a watering can.”

“You mean…?”

“Right,” growled Jack. “Cuclear energy.”

They all fell silent, pondering on the geopolitical ramifications of such a discovery.

“Hold on a sec,” added Jack in a worried tone. “Fuchsia’s champion was almost at fifty kilos, and he had six others nearly as large that were stolen this morning—where the hell are they now?”

“There were seven thermocuclear devices?” queried Parks, who had latched on to Jack’s outlandish explanation without too much difficulty, as should you. “This is very worrying. The destructive power of a group of devices wouldn’t be arithmetic but exponential—we’re talking a total yield of perhaps fifty kilotons—enough to flatten everything for a half mile in all directions.”

“Jack,” said Mary in a nervous whisper, “we were all requested to be present at the Bob Southey at seven o’clock, but no one knows who asked us.”

The implication wasn’t lost on him. He turned to look at the Bob Southey, then at all the crowds milling about. Everyone was here: himself, Ash, Mary, Parks, Briggs, Bartholomew, Vinnie, even the Bruins, who were being treated in the Southey Medical Center. Everyone, in fact, but NS-4 who’d legged it off to QuangTech. It wasn’t a siege. It was a trap.

“Mary, tell Briggs to evacuate the area immediately and then look for McGuffin. This is going to be one hell of a bang, and he wouldn’t miss it for anything. I’d start checking out distant ridges or any other good viewing points.”

Jack didn’t wait for a reply and ran toward the entrance ramp of the underground garage where he had busted Tarquin Majors—and straight into a cordon of police officers.

“You’re going to have to let me through,” he barked to the Sergeant in command. “There’s a thermocuclear device in there which could destroy half of Reading.”

“Briggs warned us about your little tricks,” retorted Chapman with a faint smile. “No one goes in, no one comes out.”

“I’m head of the NCD, Sergeant. In matters concerning my jurisdiction, I have unlimited access—you know the rules.”

“You’re right about that,” returned the Sergeant, “but you’re not head of the NCD, now, are you?”

“I’m here under DS Mary’s orders—she’s head of the NCD in my stead.”

“Think I don’t read the papers?” replied Chapman with a smirk. “She’s been suspended, too.”

“I don’t have time to argue!” yelled Jack, and he tried to push his way through, but there were four of them, and they held him tight.

“For God’s sake—”

“I’m head of the NCD,” said a voice behind them, “and you can release my associate and let us both pass.”

“You?” said Chapman, staring at the small alien who was glaring up at him. “An alien constable who no one else will work with?”

“I’m NCD and have a badge to prove it. In the event of a superior officer being incapacitated or suspended, authority devolves to the next-ranking officer. In this case, me.”