AI The oaks changed before the path did.
Rory noticed it the way she noticed most wrong things, out of the corner of her eye while trying not to stare. The trees along the Richmond Park track had been ordinary winter oaks for the last half mile, black-barked and bare against a sky the color of wet pavement. Then, past a bend she could not remember taking, their trunks thickened. Their roots lifted from the frozen ground in knotted arches. Their branches reached so high that the tops vanished into a pale mist that had not been there a minute ago.
Her phone buzzed in her coat pocket. She pulled it out. No signal. The clock read 4:17, then 4:16, then jumped to 4:43 while she watched.
"Please tell me that's a software problem," she said.
Beside her, Nyx did not cast a shadow on the frost. Everywhere else in their six-foot-two solid form, they were shadow given an edge, a human silhouette cut from a darker piece of evening, with faintly glowing violet eyes set where a face should have been. When they moved, the hem of them frayed and caught on the air.
"No," Nyx whispered. The sound came from slightly behind her left ear, though they stood on her right. "That is the place deciding what an hour is worth."
"Comforting. Thank you."
"I did not promise comfort."
They had come for Isolde, because Isolde had sent a message by way of a robin that tapped three times on Rory's kitchen window, waited until she opened it, and dropped a single silver leaf on the sill. Nyx had gone very still at the sight of it. Then they had said, in that wind-through-dry-leaves voice, that the Seer did not send invitations unless she had already seen someone arrive.
Rory still was not sure she liked being expected by a woman who lived in a fold between worlds, but Eva was missing three hours she could not account for, the Veil had been shimmering over the Thames at dawn yesterday, visible even to Rory's increasingly unreliable eyes, and Isolde Varga was the only person who might answer a question without first trying to sell her something or set her on fire.
The pendant at Rory's throat had gone quiet. The Heartstone, a deep crimson stone no bigger than her thumbnail on its silver chain, pulsed warm whenever a Hel portal breathed too close to the skin of the world. Here it lay cool and still against her collarbone, its faint inner glow dimmed to almost nothing. Not Hel, then. Somehow that did not relax her.
The standing stones appeared between one step and the next.
They ringed a stand of ancient oaks, nine stones, each taller than Nyx, each eaten by moss and carved with spirals so worn that Rory only saw them when the light shifted. Frost filled the grooves and made them shine. Beyond the ring, the air moved wrong. It shimmered, a faint distortion like heat over summer tarmac, except the park was bitterly cold and her breath smoked in front of her.
She stopped without deciding to.
"That's the Veil." Her voice came out smaller than she wanted. "Actually that. Not theory, not Silas drawing diagrams on napkins."
"A tear mended over and over," Nyx said. "A door that learned to be a wall."
"And we are walking through it because a three-hundred-year-old oracle left me foliage in the post."
"The robin was the post," said a voice from inside the stones. "The leaf was only the stamp."
Isolde stood where no one had stood a breath before.
Rory's first thought, stupidly, was hair. Silver hair to her waist, loose and unbound despite the wind worrying the oak tops, and skin that made the frost look dull. Her eyes were pale lavender, almost colorless until the light caught them, and then they were not human at all. She wore a long coat of deep green wool and no shoes. Her bare feet rested on frozen mud without sinking into it.
As she came toward them, she left no footprints.
"You are late," Isolde said to Rory. "Which is fortunate. Early would have put you here last week."
Rory looked down at the unmarked frost between Isolde's feet and her own boots. "I'm going to pretend that sentence gets less frightening if I don't examine it."
"Most sentences do." Isolde's gaze moved to Nyx and softened in a way that made Rory uneasy for an entirely different reason. "Nightwhisper. You wear the dark well today."
Nyx inclined their head. Their edges thinned. "Seer."
"You brought me the girl who asks doors why they are locked."
"I brought Aurora Carter," Nyx said, "because she asked."
Something in the stones hummed when her full name crossed the boundary. Rory felt it in her teeth. The crescent-shaped scar on her left wrist prickled, and she pressed her thumb into it without thinking.
"Inside," Isolde said, "we use the names we are given only when we mean to keep them. Come, Rory. Mind the threshold. It minds you."
She should have asked what that meant. Instead she stepped between the stones, because not stepping felt like the beginning of a different and possibly worse story, and because Isolde had already turned away with the serene confidence of a woman who had watched this exact hesitation in a vision and found it tedious.
Crossing hurt in colors.
There was no other way to hold it in her head. Cold went through her first, clean as a blade between the ribs, then warmth , then a pressure behind her eyes, and for half a second she could see the park in layers, Richmond laid over a green-gold country that stretched too far in every direction, hills rolling where London ought to have fenced the sky. She heard bells, small and distant, and under them a crowd laughing, and under that a single voice calling a name that almost sounded like hers but bent in the middle, Laila, Malphora, something wearing her shape wrong.
Her boot came down on grass.
Warm grass. Green grass, thick with clover and starred with wildflowers, white and violet and a blue so intense it looked lit from inside. It was December on the other side of those stones. On this side, sunlight poured through leaves in a long amber fall, the air smelled of honey and crushed green stems and rain that had not fallen yet, and bees drifted fat and slow between blossoms that should have been dead for two months.
Rory stood very still and breathed it in despite herself.
"Oh," she said.
Isolde glanced back, and for the first time she smiled with something that might have been sympathy. "Yes. It does that to the honest ones."
Nyx crossed after her with less trouble and more complaint from the world. Their form lost its clean edge as they passed the stones. Violet eyes flared. For an instant Rory saw something beneath the silhouette, not a face, exactly, but the suggestion of one, a man made of smoke remembering cheekbones and a mouth, and then it was gone . Nyx gathered themselves together with a visible effort.
"Your grove dislikes me," they said.
"My grove remembers what you were," Isolde said, "and has not decided what you are. Walk politely."
They went deeper.
The grove was larger inside than the stand of oaks could possibly hold. Rory understood that in her body before her mind stopped arguing. The path wound between trees whose trunks would have taken six people hand in hand to circle, trees hung with pale fruit like small moons. Drops of water fell upward from a stream beside the path, glittering as they rose into the branches and vanished among silver leaves. Somewhere out of sight, something large moved through undergrowth with a slow, unhurried tread, and the flowers turned their faces toward the sound as it passed.
"Don't eat the fruit," Isolde said, without looking back .
"I wasn't planning to."
"You were wondering what it tastes like."
Rory, whose mouth had in fact begun to water at a scent like pear and cinnamon drifting from the nearest branch, shut it. "That's intrusive."
"That is the grove. It offers what you hunger for first, so it can learn the shape of the hand that reaches."
Ahead, the path opened around a pool.
The water was black and perfectly still, and it did not reflect the trees. It reflected a sky full of unfamiliar stars, though gold-green daylight filtered through the leaves above them. Around its edge grew white flowers with centers like closed eyes. As Rory approached, the eyes opened. Every one of them was blue. Bright blue. Her blue, if she was being precise, and she really did not want to be precise just then.
She stopped at the bank. Her reflection looked up at her from among the wrong stars a second too late, and smiled a second too soon.
"Isolde."
"I see it."
"What is it doing?"
"Practicing."
Rory backed up until Nyx's cold presence brushed her shoulder. Solid enough to steady, not solid enough for warmth . The reflection in the pool remained where she had been standing for three heartbeats longer, head tilted, watching the place she had vacated, before it slipped back beneath her boots like something disappointed.
"I hate that," Rory said honestly. "I hate that a lot."
"Good," Isolde said. "Fear that arrives on time is a kind of courtesy. Ignore the pool. It is only a mirror that got above itself."
They skirted it on a path of flat white stones. Beyond the pool, the trees grew closer and the light changed again, taking on the green depth of deep water. The air cooled against Rory's face. The sounds of the grove layered and separated, birdsong running backward in bright ribbons, a woman singing far away in a language that made the hairs rise along Rory's arms, the soft ticking of insects keeping time to a clock that did not match her pulse . She could feel her own heartbeat trying to adjust, to follow that ticking instead, and she dug her nails into her palm until it remembered itself.
At the center of the grove stood a tree that made the others look young.
Its trunk split into seven great limbs, and each limb split again, and its bark was pale as bone, patterned with spirals that matched the standing stones. From its branches hung hundreds of small silver leaves, except they were not leaves. As the wind moved through them, they chimed. Each one was a thin blade of metal, leaf-shaped, no longer than her finger. Beneath the tree, the ground was bare and dark and warm-looking, scattered with offerings: a child's red mitten stiff with age, a crown of braided hair, a bowl of milk untouched by insects, a smartphone with its screen cracked in a spiderweb and its battery icon, impossibly, full.
"People leave strange things," Rory said.
"People leave true things," Isolde answered. "There is more overlap than priests admit."
She laid her palm against the pale trunk. The chiming stilled. In the sudden quiet, Rory heard the grove breathe, one long inhalation drawn through root and leaf and hidden water, and her own lungs tried to follow it and failed.
Isolde reached into a hollow at the base of the tree, a dark mouth in the bark that Rory was certain had not been there a moment before, and drew out a dagger.
Even in daylight it glowed faintly, as if it had kept a little of whatever moon had made it. The blade was slender and leaf-shaped, forged of moonsilver, longer than the ornaments in the branches but of the same family. When Isolde held it out, Rory took it before wisdom could stage an intervention.
It was cold. Not winter cold. Older than that, cleaner, the cold of deep caves and starlight on snow, and it stayed cold even as her fingers curled around the hilt. The weight of it settled into her hand like it had been measured there in advance. Along the flat of the blade, patterns moved under the surface, vines or script or veins of light, there and then not.
"It can cut wards," Isolde said. "It can cut worse things that wear wards like skin. It will not love you. Do not ask it to. Use it when the door insists there is no door."
Rory looked up. "Why me?"
"Because you are the one holding it," Isolde said, which was no answer and, Rory suspected, also not a lie. Isolde could not lie. That was the Fae compulsion, neat as a locked box. She could only stand beside the truth at an angle and let you walk into the sharp edge of it yourself. "Because a blade given is a question asked. Because the winter is turning its face toward us, and the Veil wears thin when the year dies, and something on the other side of it has learned how you smell."
From the far side of the pool, back the way they had come, Rory's own voice called her name. Perfectly. Kindly. With Eva's laugh tucked just underneath it.
Nyx's violet eyes blazed in the green gloom . Their form went thin and tall and came between her and the path without crossing the distance in any way she could track.
"Do not answer," they whispered, and this time the whisper came from everywhere the shadows touched. "Rory. Look at me and do not answer."
The voice called again, closer now, wearing patience like a coat. Isolde said nothing at all. She only watched Rory with those pale lavender eyes, bare feet planted on earth that bore no mark of her, while the silver blades above them hung silent and waiting.
Rory tightened her grip on the cold dagger. Her reflection had smiled too soon. Her voice was walking around without her. Time was leaking through her phone in both directions, and the flowers by the pool had opened their blue eyes to practice being her.
"Right," she said, quietly, to none of them and all of them. "Deeper, then."
Isolde turned toward a stair of roots descending into gold-green dark beneath the great tree, where no path had been before Rory spoke.
"I was hoping," the Seer said, "you would see it that way."