Inside her cell, with the door closed, she takes out the bottle from her robe and turns over the mattress to locate the hiding place.

Her cunning in such things amazes even herself. She has gone through it all a thousand times: how, when, where. If someone were to ask her now, she might almost say she was enjoying herself, for as a child she always liked best those bits of learning that could be applied rather than simply memorized. “You have the makings of a good dispensary assistant.” That is what Zuana said to her just now. Well, perhaps she does. But she is bound for greater things. What they are she cannot quite imagine, for some days there is barely time to think of that—of him—at all, she is so full of it: the planning, the preparations.

At night, to blot out the voice of Magdalena, she tries to imagine herself out of here. She gets as far as a room (Ferrara beyond the convent walls is an unknown city to her), not as rich as her father’s house but comfortable enough, with a fire in the grate and musical instruments all around, and she and he are in each other’s arms, the music they have been making suddenly stopped by kisses. She tries to imagine his mouth, lips soft like the inside of a ripe plum, and to find it again she brings her own open lips to the back of her hand, feeling the wet heat of her own saliva, the probe of her tongue, the ridge of teeth pulling playfully at her own skin. It brings with it a pinching in her gut that leaves her slightly breathless. In her mind their embrace is so close that she cannot see his features and she has to step back to try to reacquaint herself with his face, only the image of him remains blurred so that she feels a twinge of disappointment, almost a sense of shame, which unnerves her a little.

Never mind. Soon it will be different. Soon she will see his dear face again and remember why she loves him so.

She has made her plan. The best time will be during Carnival. With so much distraction and the excitement of performance they will have too much on their hands to police the comings and goings of a single—and now radiantly obedient— novice. And with all the activity revolving around the cloisters and the parlatorio—she has thought this through, step by step—no one will even be thinking of the storehouse by the river, where, on the other side, a boat could surely loiter in the darkness without causing suspicion.

But for him to come in or for her to go out, separately or together, they will have to get through two sets of doors: one from the river to the storeroom and another from the storeroom into the convent. And for that she needs copies of the keys. Here lies the next challenge. Apart from the master keys held by the abbess, there are two sets. The first, kept by the cellarer, is impossible; Suora Federica has a face to match the rock in her soul, and everyone knows she wears the keys next to her skin day and night. However, the gossip is that the chief conversa is less amenable to the imprint of sharp metal between her breasts and so sleeps with her duplicate set under her bolster. Although the story has it that, like all good dragons, she sleeps lightly to protect her treasure.

In which case she would no doubt appreciate a good night’s rest—a touch of that same relief as is sometimes generously offered to those on their way to the gallows, though it would provoke dreams that would torment them further should they ever have the good fortune to wake up again. It is not easy even with the poppy syrup in her hands, for she has to find an innocent way to administer it. Candida has the wherewithal but she is too savvy for her own skin to take on something that would almost certainly end with her exposure. No, there has to be another way.

She slips the vial through the tear into the mattress, next to where the wax block is already nestling amid the horsehair and straw.

The bell for Sext sounds.

PERHAPS IF ZUANA had had more time. With time she might have thought further about the abbess’s story. With time she would have checked the supplies and samples in her room more rigorously. But a few minutes later the bell for Sext sounds, and between prayer and work and more prayer sometimes there is simply not enough time.

Over the next twenty-four hours the malady spreads further, strengthening as it goes, and in one of the infected sisters the fever becomes dangerously high. With the convent concert and play only a few weeks away, there is a growing concern that Santa Caterina will be too ill to participate or—more important—to entertain and impress others.

The next morning’s work hour finds Zuana in the dispensary sucking on a wad of ginger root to counteract the nausea that is rising in her stomach and ignoring the way her head is burning. She is ill, that is clear enough. But she is not yet incapacitated. Either the contagion will prove too strong for her or she will resist it. There is no point wasting time wondering which it will be. It is more important to find a way to fight back.

She has seen all the symptoms before in varying computations, the rhythm and severity transmuting over the years. One winter such an infection might come early, moving like a fast wind across a field, bending but not breaking any of the crop. Another year it might wait, feeding off the damp and fog until it is fat with fetid water, and affecting the oldest or those with moist humors worst, drowning more than a few in their own phlegm, only to be replaced the next year by one that favors heat rather than water, burning up rather than pulling down.

Remember, it is always best to try to contain rather than rely on curing, since by the time you have found a treatment that works the malady has often done its worst. During his lifetime her father had kept notes through the most virulent outbreaks, comparing the ages and constitutions of the ones who died with those same attributes in the ones who survived.

“That is all very well, but once started it is easier said than done,” Zuana murmurs, as she mixes up another batch of mint and rue vinegar water for the fever.

He had found that those people who nursed others— mothers, doctors, priests—were often most affected, which was not so surprising, for as well as their proximity it could be that God chose to take to Him the kindest and therefore those He loved best. Except that He also took at least as many sinners as would-be saints. While some resisted with tonics, others remained healthy without, as if they held the cure already within themselves. Then there were the ones who were not helped at all, even when they took anything and everything available.

As to the causes—well, the answers were as plentiful as the contagions. In his last years, her father had been drawn to the theory (which, like many, was built on an ancient one) of a physician colleague in Verona who argued that such diseases traveled by means of tiny malevolent seeds in the air that sat inside clothing and materials and, having entered the body, attacked and overcame the healthy seeds they found there, turning them into an enemy force within. Yet if they were so small as to be invisible, how could any doctor tell where they were hiding? Why were some more dangerous than others? And how, short of burning everything, even the air itself, could we destroy them? To the lack of answers he had brought only more questions. In the end, the outcome was the same: if it was not actually the plague or the pox, whatever it was eventually moved on, only to be replaced by something else the next year, and then another, not entirely unlike it, two years after.

In some ways Zuana is lucky to be kept so busy for if she were not she might find herself thinking of that winter, sixteen years ago, when her own life had started to unravel. The weather itself had been unusual that year, mild right into the beginning of February, and the infection, when he contracted it, had seemed benign enough, though he was old by then—over seventy—and already no longer quite as boundless in his energy. He had sneezed and wheezed, then turned hot and cold, but after two days in bed with a fever, which she had treated according to his instruction, he had got up again, declaring himself to be cured and with the appetite of a horse.