With that he stripped off the beard. “Bess!” he yelled. “Bess, come down here. Your husband has returned from the grave.”

There was a scream from up above and Bess came flying down the stairs. We were in the midst of a touching reunion when there was a bang at the front door. We froze. Houdini’s mother went to answer it and I heard Mr. Wilkie’s calm, deep voice. In he came, and in his wake was Daniel.

Daniel pushed past him and swept me into his arms. “Thank God,” he whispered. “Thank God.” He held me close, his heart thumping against mine. Then he released me, holding me at arm’s length and frowning at me. “I’ve only heard the sketchiest account of what you might have been doing, but it’s never going to happen again, do you hear that? I utterly forbid it.”

“Don’t worry,” I said. “I have no aspirations to become a spy.”

“I can’t believe that you kept it from me,” he said, his eyes flashing angrily now. “You deliberately lied to me.”

“I was sworn to secrecy,” I said. “I had no choice. I’m sorry.”

“Miss Murphy has just endured a most harrowing experience,” Houdini said, and he recounted it.

Wilkie sighed. “I am sorry to have put you in such danger,” he said. “We have long suspected that one of my own men was a double agent, but I had no way to make him show his hand.”

“So you used me as bait,” I said angrily.

“I rather fear the answer to that is yes,” he said. “But it never occurred to me that he’d reach New York before me. Or that he’d realize you had discovered his true identity.”

“I did more than that,” I said. “I found out why the German agents were so eager to keep Houdini from meeting you.” I looked across at him.

“I was taken around a factory,” Houdini explained. “They were proud to show off their engineering superiority. I glimpsed a design for an underwater craft that could transport many men undetected. And then, on another occasion, when I overheard a plan to launch a surprise attack on the East Coast of the United States, I realized how dangerous this craft could be.”

Wilkie nodded. “We were half expecting something like this.”

“Why would the Germans want to attack the United States?” Daniel asked. “Do they want to wage war against us? Do they have the might to do so?”

“Not yet,” Wilkie said. “They merely mean to alarm us. They wish to expand their presence in the Americas—to establish colonies in Central and South America—and they think such surprise attacks would make a good bargaining tool with the country that dominates the Americas.”

“How foolhardy of them,” I said. “Smaller incidents have led to out-and-out wars, haven’t they?”

He nodded.

“So what will happen now?”