"Sorry to take so long," Austin said, savoring the cool brew that trickled down his throat. "We came as soon as we could. There was background noise when you called, and I'm not sure I understood you correctly," Austin said. "You said something about the nursery rhyme, but I didn't get the rest."
"After you left for Manassas, I started fooling around with Karla's bedtime rhyme. The title, 'Topsy-Turvy,' and some of the lines fit in with what we know about polar shift. It seemed too close to be coincidental."
"I've found that few things are coincidental," Austin said. "However, it's a coincidence that I'm still thirsty and there's an untouched beer on the table."
"I'm too cranked up to drink." Barrett shoved the beer across to Austin, who shared half of it with Karla.
"We were talking about coincidences," Austin said.
Barrett nodded. "Kovacs was an amateur cryptologist. I started with the premise that the rhyme might be a cipher. I guessed that the topsy-turvy couplets were simply 'nulls'-letters or words placed in a cipher to confuse-so I put them aside and stuck with the main body of the verse. A cipher is different from a code, which usually requires a codebook to make the translation. To unlock a cipher, you have to have a key, which is included in the message itself. One phrase jumped out immediately."
"The key is in the door," Karla said without thinking.
"That's the one! It seemed obvious, almost too obvious," Barrett said, "but Kovacs was a scientist who would have been obsessed with precision. It would have been more precise for him to have said that the key is in the lock."
"The key was in the word door itself," Austin said.
"That was my thinking," Barrett said. "Door became my key word. You have to look at code breaking in a couple of ways. At one level, you're dealing with the mechanics of things, such as word or letter transpositions and substitutions. At another level, you're looking at the meaning of things." Seeing his explanation greeted with blank looks, he said, "What does a door do?"
"That's easy," Karla said. "It separates one room from another. You have to open and close it to pass through."
"Correct," Barrett said. "The word's opening letter is D."
He grabbed a clean napkin and with his ballpoint pen wrote:
DEFGHIJKLMNOPQRSTUVWXYZ
ABC
"This sets the pattern of letters for the plain alphabet. I took the last letter in door and used it in the same configuration for the cipher alphabet."
"Let me try," Karla said. Taking the pen, she wrote:
RSTUVWXYZABCDEFGHIJKLMN
OPQ
"I'm buying you a ticket to Bletchley Park," Barrett said, referring to the British code-breaking headquarters during World War II.
"Using the alphabets to write the word message, you'd still get gibberish." Karla stared at the word with disappointment in her eyes.
"Your grandfather didn't want to make it too easy. I came up with the same result. Then I went back to the key word. D and R are four spaces apart in the word door. I wrote down every fourth word in the main verse, but my gut feeling told me that it was too much. So I tried every fourth letter. Still nothing I could sink my teeth in. Then I thought, D and R are fifteen letters apart in the alphabet. I used that formula in the poem and picked out every fifteenth word. Then I used the plain and cipher alphabets to attempt the cryptanalysis. Are you still with me?"
"No," Austin said.
"Yeah, that's what happened to me too," Barrett said with a grin. "So I cheated. I ran the whole bloody mess through a computer." He reached into his jacket pocket and produced a computer printout. "This is what I got."
"A mishmash of vowels and consonants, but no words," Karla said.
"I tried everything. I called up an MIT professor who spoke Hungarian and ran it by him. No go. Then I remembered Kovacs spoke Romanian, and called up a guy who runs the Transylvania Restaurant back in Seattle. He couldn't make heads nor tails of it. I would have torn my hair out, if I had any. I went back to the words that I had discarded, particularly turvy-topsy. I thought maybe it applied to what I was doing."
"How could you turn the message upside down?" Karla said with skepticism.
"I couldn't. But I could interpret the words loosely, and run it backward, like the second line of the poem. Which is what I did.
Still didn't make sense. Then I had an epiphany. As I rode around on my bike, I realized that it wasn't supposed to be words. It was exactly what it was, a string of letters, more or less. Once I jumped that hurdle, I figured that there were numbers in the message as well. Back to the computer. Certain letters were indicators that meant the next letter was actually a number. A preceded by another letter equals 1, B equals 2 and so on."
"You've lost me again," Austin said. From the puzzled look on Karla's face, she was wandering around in cipher land as well.
Barrett set the computer page aside and picked up the napkin in both hands. "This is an equation."
"An equation for what?" Austin said.
"By itself, the message doesn't make sense, but we've got to look at it in context. Kovacs intended that the message would be seen by only one person: Karla. He said she would always have the poem when you needed it."
"Are you saying what I think you're saying?" Austin said.
"I just figured this out a few minutes ago, so I can't be sure until I put it to the test," Barrett said. "But Kovacs could have given us a set of electromagnetic frequencies."
"The antidote," Karla whispered.
Austin gingerly picked up the napkin as if it would fall apart. "This is the frequency that can neutralize a polar shift?"
Barrett's Adam's apple bobbed a couple of times "Hell, I hope so," he said.
Karla leaned over and kissed Barrett on the top of his bald head. "You've done it."
Barrett looked downhearted for someone who had saved the world. "Maybe. I'm afraid we don't have much time."
"What do you mean?" Austin said.
"After our meeting, I listened to the phone conversations transmitted by the electronic bug you planted on Gant's estate. He and Margrave talked. They've left the country by now."
"Damn," Austin said. "Where did they go?"
"I don't know. Margrave never got around to telling me the plans for the final phase. But it's not where I'm worried about, but what. I think they're about to put their plans for a polar reversal into effect."
"Any estimate on how long we have?"
"Hard to tell," Barrett said. "The target location is in the South Atlantic. I wasn't in on the final discussions, so I don't know the exact spot. Once they're on-site, it's only a matter of hours before they pull the switch."
Austin handed the napkin back to Barrett. "Can this equation be translated into something we can use to actually neutralize the reversal?"
"Sure. The same way E = mc2 was translated into the Bomb and nuclear power. All you need are the resources and the time."
"You'll get all the resources you need. How long will you need to build something that will do the job?"