“Not the substance but the tone of it,” Sophie returned, raising her voice to match the volume of the wind. “Her previous letters, you know, written after the Whigs invited your husband to England, were petulant. Bitter. But this one is-or was-written in a haughty tone. Triumphant.”

“Something has changed in the last month or two-?”

“That is what she believes, I fear.”

“She phant’sies we are never coming at all. She’s going to give the throne to the Pretender.”

Sophie said nothing.

“But the throne is not all hers to give away. Parliament has some say in the matter. What could have occurred in the last few weeks to give the Jacobites such confidence?”

“A blow has been struck against the currency. An interruption in the flow.”

“That is just the sort of thing I was talking about a moment ago.”

“Perhaps you are a witch, dear, with powers of divination.”

“Perhaps I receive unscheduled visits from ‘horrid Englishmen.’ ”

“Aha!” Sophie glanced in the direction of the great fountain.

“Something must have gone awry at the English Mint.”

“But Sir Isaac Newton has charge of the Mint! I have been studying it,” Sophie said proudly. “When I’m Queen of England we shall all go to the Tower of London and see it.” Then she slapped her knee, meaning it was time to get up. For it was absolutely raining now, and search parties had probably been sent out from the Palace. Caroline got to her feet and gave Sophie an arm, helping her up off the bench. Meanwhile Sophie went on, “Sir Isaac has reformed the English coinage, which was the world’s worst, and now it is the best.”

“But this proves my point! All you are saying is that English coins have an excellent reputation…Let’s get out of here.” Caroline led the way this time, ushering Sophie out the nearest gate and onto one of the radiating paths. But then she pulled up short. The way back to the Palace was not obvious, even to one who knew the garden well. Sophie sensed her hesitation. “Let us wait it out in the pavilion,” she decreed, inclining her ruined fontange toward a diagonal path that would conduct them to the edge of the garden, where a stone dome overlooked the canal.

Caroline did not favor this idea because it would take them to a distant and unfrequented corner, and the way was hemmed in by dense wooded plots that were black and opaque and loud in the rain.

“Don’t you think we should return to the great fountain? Someone should be looking for us there.”

“If someone finds us, we shall have to stop talking!” Sophie answered, very provoked.

That was that. They turned their backs on the fountain and entered into a cleft between stands of trees. “It’s only water,” Caroline said philosophically. But Sophie seemed to have had quite enough of it, for she yanked on Caroline’s arm and began pulling her onwards, trying to quicken their pace. Caroline let herself be pulled.

“I take your point,” Sophie said. “A coinage based upon silver and gold has a sort of absolute value.”

“Like Sir Isaac’s absolute space and time,” Caroline mused. “You can assay it.”

“But if value is based upon reputations-like stocks in Amsterdam-or upon this even more nebulous concept of flow-”

“Like the dynamics of Leibniz in which space and time inhere in relationships among objects-”

“Why, then, it becomes unknowable, plastic, vulnerable. For flow may have some value in a market-place-and that value might even be real-”

“Of course it is real! People make money from it all the time!”

“-but that sort of value cannot survive the refiner’s fire at a Trial of the Pyx.”

“What on earth is a Pyx?” Caroline asked. But no answer was coming. Sophie pulled sharply on her arm and at the same moment fell into her. Caroline had to bend her knees and whip her free arm round Sophie’s shoulders to avoid falling down. “Grandmama? You wish to go in this way?” She glanced at the dark stand of trees to the left side of the path. “You wish to visit the Teufelsbaum?” Perhaps Sophie had changed her mind, and wished to take shelter under the trees instead of going all the way to the pavilion.

Some sound came out of Sophie’s mouth that could not really be understood. The clatter of raindrops on leaves made it difficult to hear even well-spoken words. But this utterance of Sophie’s had not been well spoken. Caroline doubted that it was even words. Relying on Caroline for support, Sophie shuffled and hopped on one leg until she had brought them face to face with an iron gate. For the plot of the Teufelsbaum, the Devil’s Tree, was surrounded by a wrought-iron fence as if it needed to be kept in a cage.

Sophie nodded at the gate, then looked up at Caroline with a kind of lopsided sneer: half of her face pleading, the other half sagging and vacant. Caroline reached out for the handle of the gate. At the same moment that the cold wet iron touched her skin she knew that Sophie had suffered a stroke. For this was not the first half-paralyzed face Caroline had ever seen. The symptoms were more difficult to recognize in a face she knew so well and loved so much. For a moment she froze with a hand on the gate-latch, as if some spell had turned her own flesh to cold iron. She ought to go for help, to find the doctors.

But then Sophie did something telling, which was that she looked up and down the garden path, and she did it furtively. This from someone who had never been furtive in her life.

Sophie could not speak and could hardly stand up, but she knew what was happening. She was afraid of being seen. Afraid of being rushed to the Palace, bled by the surgeons, pitied to her face and mocked behind her back. Her instinct was to hie to the deepest and darkest part of the garden and to die there.

Caroline shoved the gate open and they stepped into the dark.

The Teufelsbaum was a curiosity that Sophie had brought back from the family holdings in the Harz Mountains: a worthless tree that crawled along the ground and climbed up things, with all the mass and might of a great tree, but the writhing habit of a vine, enclosing other things and growing round them. Its boughs twisted round and divided and forked and kinked bizarrely. The bends looked something like elbows and knees, and the smooth bark and sinewy shape of the wood made the whole thing look like unidentifiable limbs of strange animals, melted into one another. The woodcutters of the Harz hated it, and cut it back wherever they could, but here Sophie had given it leave to spread. Now the Teufelsbaum returned the favor by embracing Sophie and Caroline in its sinuous arms. Caroline settled Sophie down in a crook of the tree, up off the cold ground, and then sat on a flat place and cradled Sophie’s head in her lap. The rain-shower had now abated somewhat, or perhaps the leaves gentled it. Time became stretched and immeasurable as they listened to the rain, Caroline stroking Sophie’s white hair, and holding the one hand that had not lost its power to grip back. But the garden was a place of quiet and of relaxation. Presently Sophie relaxed her grip on Caroline’s hand, and on the world.

Caroline had a long list of questions she had been meaning to ask Sophie, concerning how to be a Queen. She could have asked them there under the Teufelsbaum, but it would have been tactless, and Sophie would not have been able to answer.

Or rather she couldn’t have answered with words. Her true answer, the one that mattered, had been arranged long in advance: it was this moment and this place. Sophie’s dying here was the last thing she said to Caroline.

“I am the Princess of Wales,” Caroline said. She said it to herself.