Zorzi's arm was still stretched out and Bravo saw an eagle in midflight tattooed on his forearm.

Seeing the direction of Bravo's gaze, Zorzi chuckled. "I wear the eagle with pride, Bravo. Only six or seven families in all of Venice were allowed to display the eagle or the lily on their coat of arms. My family goes all the way back to the seventh century, further some say, all the way to the founding of Rome."

"Zorzi, yes," Bravo said thoughtfully. "Your family is one of the Case Vecchie, the old houses. The twenty-four founding families of the Republic."

Zorzi raised his eyebrows. "Now I am truly impressed. Few people know this, others disbelieve the claim. Nonetheless, it is valid and binding."

They walked a little farther away along the shore. The sunlight beat down on the water of the lagoon, turning it to the color of molten metal. Shore birds swooped and called amid the rush beds. Farther out were a series of barene, salt-flats-clay and sand, really-deposited over time by the currents, feeding ground for warblers and marsh harriers alike.

"I will leave you to read the tea leaves left for you by your father," Zorzi said, and he strode off toward two of his men some five hundred yards down the islet shore.

Bravo, grateful to be alone during this process, looked at the square lock. It was the same size and depth as the lock in the underwater safe in St. Malo. He inserted the second cuff-link key into the lock, turned it one way, then the other. The steel beggar's purse popped open.

Inside, he discovered a rolled-up slip of paper with another cipher handwritten on it. He studied it carefully. This one was naturally enough of a different and more complex nature than the modified substitution code devised by Caesar. Bravo could see that it required a code book, so it stood to reason that his father had supplied him one.

He took out the small, ratty notebook. It was the only possible place his father would have inscribed the code protocol. Climbing the seawall, he sat on the white stone, looking out into the fog-gripped lagoon. Water and sky were indistinguishable, all was reflection, and once again he was gripped by this sense of inversion, as if Venice itself was a lens through which he was now forced to look.

With an almost obsessive patience, he went through the notebook, searching for page, line and letter numbers, the usual sources for the key to this form of cipher. Of course, he could start by listing the letter frequencies in the encrypted text-for instance, in English e was the most used letter and t the second most used. Each letter of the alphabet had a percentage of frequency. Also, vowels tended to associate with one another-such as ou and ie, whereas consonants rarely did.

Letter-frequency decryption went all the way back to the ninth century. The Arabic scientist Abu Yusuf al-Kindi provided the first known description of it. However, al-Kindi's code-breaking method was most useful in lengthy messages-the longer the encrypted text, the better the letter-frequency method worked-and this text was short. Second, and more important in this instance, was that letter frequency changed depending on which language one was using. For instance, the two most used letters in Arabic were a and l. Bravo knew, however, that there would be no less than five different languages in the text. This was typical of his father, who loved nothing better than to take a classic cipher and stand it on its ear so that it would baffle even an expert code-breaker.

With his eidetic memory, Bravo could, of course, have used these methods to laboriously try to break his father's cipher, but he had neither the time nor the confidence that he would be successful. Therefore, he required the key.

Once again, he went through the notebook, this time from back to front. On one page near the middle of the notebook, he came across the note, "There must be a reason for all this movement." By itself, it meant nothing, but on the next page forward, he came across the same sentence reversed, as if his father was working out a new cipher. When it came to ciphers, his father loved inversions. Bravo might not have noticed this one had he not been leafing through the notebook from back to front. Taking out a pen, he put the two sentences together, one right beneath the other. There were letters that lined up: t and e, which was interesting if one were thinking of letter-frequency decoding, but Bravo knew this was just the sort of false lead his father loved to insert into his cipher keys. But it was a clue that the key was a variant of the 3DES, the triple Data Encryption Standard, developed in the mid 1970s. E was the fifth letter of the alphabet, t, the twentieth. Subtracting 5 from 20 left 15. Subtracting 2, for the two letters, e and t, left him with thirteen. M was the thirteenth letter of the alphabet. He turned his attention to the m, which was the sixth letter in the first sentence, the fourth in the second sentence. He added the two, then subtracted the number of matching letters that came before the m's. The result was eight. He had his key.

Bent over, he moved through the cipher. When he was done, this is what his father had left him: "Remember where you were the day you were born and the name of your third pet."

He'd been born in Chicago, but try as he might he couldn't figure how he could possibly connect that with anything in Venice. At length, he went on to the next bit. His third pet had been a dog-a stray mutt so disheveled-looking he'd called her Bark. So he had one piece of the puzzle his father had meant for him to solve.

Remember where you were… He was born in St. Mary of Nazareth Hospital.

But how could that help him? There must be over a thousand statues of Mary in the city, and, in any event, what possible connection could Mary of Nazareth have with the word bark?

He looked up. The afternoon had slipped away. A cool breeze, marking the onset of sunset, ruffled his hair. His shirt was stuck to his back. With a sigh, he closed the notebook and placed the coded paper back in the alms box. Then he clambered down off the seawall in search of Paolo Zorzi.

There was a moment when Anthony Rule felt lost at sea. As was typical in summer, an afternoon mist had risen, bom of the heat and the humidity that lay over Venice like a shroud. He was adrift in the whiteness with only the pulsing disk of the sun visible as it heated the atmosphere. For a moment his hand rested on the wooden tiller of the topo-a light sailboat used for fishing-without trying to guide it in any particular direction. He felt a kind of fierce elation in being lost, absolutely invisible to the rest of the world, as if now he could be anyone he chose to be. The sense of freedom was enormous.

He had passed south of Burano with its lace makers' shops, so colorful they looked for all the world like the set of a merry operetta. He was a skilled and crafty seaman: he loved boats of all kinds and felt as at home on the water as he did on dry land. Getting the owner to trust him with his topo was only a matter of two hundred euros in addition to the normal hourly rate, which Rule knew was inflated. He paid the tariff in advance without bargaining. Better to have the owner think him stupid and forget him than to be clever and stick in the man's memory.

The topo felt good under him-solid and responsive. It had been made in Chioggia, where they were first created, and he felt comfortable in it, almost as if it were a part of him.

In Dreux, he had dealt with the Knights of St. Clement in the usual fashion, but ever since the rescue in St. Malo his mind had been focused on Bravo. After talking with him for five minutes, he had cursed himself for forgetting just how intelligent and resourceful his "nephew" was. That was when he'd decided to alter his mission. His elite standing allowed him this singular flexibility, and so he had followed Bravo and Jenny to Venice. Quite naturally, his concern skyrocketed when he observed Paolo Zorzi's preemptive move on the bridge near the Church of l'Angelo Nicolo`. He knew full well Dexter's feeling toward Zorzi, and now that Zorzi had Bravo the situation, already tenuous, was on the brink of disaster.