I t was the wettest day since Noah. It also happened to be Saint Valentine’s Day, but I was not in a loving mood. The saint himself would have cursed the weather.

Maestro Nostradamus had been even snarlier than usual all morning. Then, halfway through the afternoon, he rattled off a list of reagents he needed for his experiments and ordered me to go out and buy them. I complained, reasonably, that he already had stocks of all of them on the shelves above his alchemy bench. No, he needed more and right away. Worse, since Giorgio, our gondolier, had been given the day off to attend a nephew’s wedding, I would have to go on foot.

I came home when the stores closed, two hours after sunset. I was wet, cold, tired, and late for supper. I found the Maestro in his favorite red velvet chair, dangerously close to the fireplace, with his nose inside a book. As always he was wearing his black physician’s gown; the straggly hair dangling under his hat shone silver in the candlelight.

“Cinnabar,” I said, setting the packets in a row on my side of the big desk, “birthwort, hellebore, realgar, aconite, nux vomica, and powdered stibnite. Two ducats, five soldi.” I counted out the change.

“No dried virgin’s glove?”

“Not a speck of it in the city. Old Gerolamo says he hasn’t carried it in ten years. Yes,” I added before he could ask, “I checked every herbalist in Venice, and every apothecary. I even tried the Ghetto Nuovo.”

He grunted. “You paid too much.”

“That was the realgar. It’s a good piece. Make a nice pendant on a lady’s breast.” I put the coins in the secret drawer where we keep the petty cash.

He sniffed disapprovingly. His disposition had clearly not improved while I was out. “Go and get dry. You have work to do tonight.”

I said, “Yes, master,” politely and headed off to my room. By the time I was toweled and dressed, the Angeli family had returned from the wedding-Giorgio, Mama, and their current brood. I ate in the kitchen, where the children’s excited jabber and two helpings of Mama Angeli’s excellent sardoni alla greca soon restored my normal good humor. I strolled back along to the atelier to learn what my master wanted of me, wondering whether I would get any sleep at all.

You think an astrologer’s apprentice is accustomed to staying awake all night to aim cross-staffs and quadrants at the stars? Then you are wrong, because the celestial science is pursued by day, with pen and paper at a desk, calculating aspects and ascendants from ephemerides. I admit I sometimes have to waste valuable sleeping time up on the roof recording the Maestro’s observations of comets and other meteoric phenomena, but not often. Besides, that night the rain would have blinded us.

I do not mean that he never keeps me up to ungodly hours. He does. Seeming to need almost no sleep himself, he loses track of time. He may spend a long evening instructing me in arcane lore until I am cross-eyed and all reasonable men have gone off to bed-and then decide to dictate lengthy letters to correspondents all over Europe. When that happens, he is quite capable of keeping going until dawn. I, on the other hand, do enjoy my sleep. When I stay up all night by choice, it is for pleasure, not business.

I was surprised to find the big room deserted and dark, the fire dwindled to embers. The Maestro had said he had work for me, but there were no written instructions on the desk. He had not just gone to the privy, because he had doused all the lamps except a single candle, but that one stood on the slate-topped table holding the great globe of rock-crystal that he uses for prophecy. It had been draped in its usual velvet cover when I was there earlier, but that had now been removed, revealing four lines of text scrawled on the slate itself.

Now I understood his curdled mood. Clairvoyance is exhausting and drains him. He had not had time to go into trance while I was changing and eating, so he had done it while I was out. I wondered if he had sent me off on that wild, drenching trek around the apothecaries’ shops just to keep me out of his way, but that seemed unnecessarily callous even for him.

One of my many duties is to copy out his prophecies in a legible hand, for his writing is atrocious at the best of times and execrable when he is foreseeing. I fetched two lamps, my writing implements, and the big book of prophecies. Transcription proved unusually easy, which implied that the events it foretold were near at hand. I had known him to produce much worse cacography and was confident that I was reading it correctly. Nevertheless, when I covered the table, I left the writing in place so he could approve my reading in the morning.

When Death puts up Death upon a vain course,

The Serene One moves and is unmoved;

Wisdom has departed and Silence is deserted,

So the brave Riddler must guard the treasure.

The Maestro’s prophecies are always couched in imprecise language, but this is not trickery-he is often as mystified as anyone, for he retains no memory of writing them or what he has foreseen. We have spent days trying to interpret some of his gibberish. By comparison, this quatrain seemed positively lucid, and he obviously expected me to reach the same conclusion he had, at least about the final line.

When I was growing up in the parish of San Barnaba, most of my playmates were sons of impoverished nobles. Having no wealth, they would brag instead of their ancient lineages. Venice has been a republic for nine hundred years and some boys could claim descent from very early doges. I could always end their arguments, because my family name is Zeno. The Zenos of Venice have produced one doge and many great heros, but I would claim to be a descendant of the philosopher Zeno of Elea, of the Fifth Century BC, who was known for his riddles. Then all the rest of them would pile on top of me. It did end their arguing, as I said, but did me no good, other than eventually teaching me to keep my mouth shut. There are other Zenos around the city, but we are not on speaking terms. I am the Maestro’s guardian. The Riddler was me.

I had intended to bottle and label the reagents I had purchased in the afternoon, but the quatrain’s warning seemed more urgent. In search of a second opinion, I locked up the atelier and went back to my room. There I unwrapped my tarot deck and took a reading, laying out the spread on my bedcover. It almost made my hair stand on end.

I favor a simple five-card cross, which the Maestro scorns as simplistic, but which usually gives me good short-term guidance. It begins with a face-up card to represent the question, the present, or the subject. If the first card produces nothing significant, you can try once or even twice more, but a third denial risks desensitizing the deck. My deck was very well attuned and right off gave me the jack of cups, which always means me, the alchemist’s apprentice. I dealt four cards around it, face down, to make the cross.

The one below represents the past, problem, or danger, and there I turned over Justice reversed. The card on my left-which is the subject’s right, of course-denotes the helper or path, and there I found the Emperor reversed. The card at the top of the cross tells the future, objective, or solution, and was Death, also reversed. The fourth arm of the cross is the snare to be avoided, which in this case was the four of swords. The presence of three of the major arcana implied a very strong reading and the overall spread was definitely a warning, especially the reversal of Justice. I admit I did not understand the counsel it was offering. The Maestro was clearly missing and the reversal of all three trumps suggested no clear-cut solution. The four of swords was worrisome, although not as frightening as either the three or the ten would have been.