“It is not uncommon to start a message with the word ‘the.’ It is also not uncommon to use a key that begins with the word ‘the.’ If the codemaker does both of these, then the first three letters of the message will always read the same: M, O, I. And he will have given away part of what he is trying to hide.”

“How did you discover this?” I said, amazed.

“I have spent my lifetime studying codes. Much failed hunting, a few gems unearthed. At any rate, knowing something about the key may prompt the decipherer to realize…”

He went on talking, but I wasn’t listening. I stared at the message, and the code, and the exercise I’d just finished. Then I sprang from my seat.

“I know,” I said. “I know what the key is.”

CHAPTER 15

THE SPYMASTER STUDIED MY FACE. “Do tell.”

“It’s here,” I said. “Right here in the message. I can’t believe I didn’t see it.”

I turned the letter I’d received toward him.

“The instruction, before the code. It says, ‘You will know the key when you see the truth. Remember Paris.’ I thought they were talking about what happened in France: the assassins, or their search for the lost Templar treasure, something like that. But when we were in Paris, trying to solve the riddles, Tom pointed something out.

“He noticed that for all the old clues the Templars left, the solution was always literal. That is, you’d think the puzzles were confusing, but if you read each clue exactly as written, you’d understand what they really meant.

“So let’s do the same. Take this line literally. You will know the key when you see the truth.”

And I circled the words.

You will know the key when you see

the truth. Remember Paris.

“When you see… ‘the truth.’ ” Walsingham raised an eyebrow. “Fascinating.”

He motioned for me to try it. I wrote the code out, the key THETRUTH above it. Then I got to work. Even after only half the code, I knew I’d found what we were looking for.

T H E T R U T H T H E T R U T H T H

M O I U R H J B X A M G X B H B L L

T H E B A N Q U E T I N G H O U S E

“The Banqueting House,” I said.

“Do you know where that is?” Walsingham asked.

“It’s part of the palace. Just outside.” I frowned. “But what does it mean?”

“I suppose you’ll have to go find out.”

I looked at him, surprised. “You’re not going to take over?”

“Why would I?”

“Well… you’re the m—you’re in charge. I just thought…”

“This message was not meant for me,” the spymaster said.

“You still solved it.”

“No. I recognized a pattern, and educated you. The solution was in your head, not mine. Only you knew the secret of Paris.” Walsingham pushed the letter toward me. “Whoever sent you this appears to be trying to help. They have chosen you as their contact. I see no reason to replace you. I suspect they would not even permit it.