I could just go home. I know the way.

But if Mr. Gray had been willing to risk his life for what he wanted, surely she could be as brave. She wondered if he was alive. She was surprised by how much she desperately hoped that he was.

She revised the note in her head.

Going into timeless caverns to search for ex-boyfriend. If it looks like I will miss Blue’s graduation, send help.

P.S. Pie is still not a meal.

P.P.S. Don’t forget to take the car in for the oil change.

P.P.P.S. Look for me at the bottom of a mirrored lake.

A voice whispered in her ear. Someone from the future, or the past. Someone dead or alive or sleeping. It wasn’t really a whisper, Maura realized. It was just hoarse. The voice of someone who had been calling for a long time without an answer.

Maura was a good listener.

“What did you say?” she asked.

It whispered again: “Find me.”

It wasn’t Artemus. It was someone else who’d gotten lost, or was in the process of getting lost, or was going to get lost. In these caverns, time wasn’t a line; it was a mirrored lake.

P.P.P.P.S. Don’t wake the third sleeper.

1

Do you think this is actually real?” Blue asked.

They sat between ascendant oaks under a stolen summer sky. Roots and rocks buckled up through the moist ground around them. The hazy air was nothing like the overcast fall chill they’d just left behind. They had longed for summer, and so Cabeswater had given them summer.

Richard Gansey III lay on his back, gazing up at the muzzy warm blue above the branches. Sprawled in his khakis and citrus-yellow V-neck sweater, he looked indolent, tossed, a sensuous heir to the forest around him. “What is real?”

Blue said, “Maybe we all come here and fall asleep and have the same dream.”

She knew it was not true, but it was both comforting and thrilling to imagine they were so connected, that Cabeswater represented something they all thought of when they closed their eyes.

“I know when I’m awake and when I’m asleep,” Ronan Lynch said. If everything around Gansey was soft-edged and organic, faded and homogenous, Ronan was sharp and dark and dissonant, standing out in stark relief from the woods.

Adam Parrish, curled over himself in a pair of battered, greasy coveralls, asked, “Do you?”

Ronan made an ugly sound of scorn or mirth. He was like Cabeswater: a maker of dreams. If he didn’t know the difference between waking and sleeping, it was because the difference didn’t matter to him.

“Maybe I dreamt you,” he said.

“Thanks for the straight teeth, then,” Adam replied.

Around them, Cabeswater hummed and muttered with life. Birds that didn’t exist outside the forest flapped overhead. Somewhere close by, water ran over rocks. The trees were grand and old, furred with moss and lichen. Perhaps it was because she knew the forest was sentient, but Blue thought it looked wise. If she let her mind wander far enough, she could almost feel the sensation of the forest listening to her. It was hard to explain; it was sort of like the feeling of someone hovering a hand just over your skin, not quite touching.

Adam had said, “We have to earn Cabeswater’s trust before we go into the cave.”

Blue didn’t understand what it meant for Adam to be so connected to the forest, to have promised to be its hands and eyes. She suspected that sometimes, Adam didn’t, either. But under his advice, the group had returned again and again to the forest, walking between the trees, exploring carefully, taking nothing. Walking around the cave that might hold both Glendower — and Maura.

Mom.

The note she’d left more than a month before had not indicated when she intended to return. It hadn’t indicated whether or not she intended to return at all. So it was impossible to tell if she was still gone because she was in trouble or because she didn’t want to come home. Did other people’s mothers vanish into holes in the ground during their midlife crises?

“I don’t dream,” Noah Czerny said. He was dead, so he probably didn’t sleep, either. “So I think it must be real.”

Real, but theirs, just theirs.

For a few more minutes, or hours, or days — what was time, here? — they lazed.

A little away from the group, Ronan’s younger brother, Matthew, nattered away to their mother, Aurora, happy for this visit. The two of them were golden-haired and angelic, both of them looking like inventions of this place. Blue longed to hate Aurora because of her origin — literally dreamt up by her husband — and because she had the attention span and intellectual prowess of a puppy. But the truth was that she was endlessly kind and upbeat, as compulsively lovable as her youngest son.

She wouldn’t abandon her daughter right before senior year.

The most infuriating part about Maura’s disappearance was that Blue didn’t know if she was supposed to be consumed by worry or anger. She vacillated wildly between the two, occasionally burning herself out and feeling nothing at all.

How could she do this to me now?

Blue lay her cheek against a boulder covered with warm moss, trying to keep her thoughts even and pleasant. The same ability that amplified clairvoyance also heightened Cabeswater’s strange magic, and she didn’t want to cause another earthquake or start a stampede.

Instead, she began a conversation with the trees.

She thought about birds singing — thought or wished or longed or dreamt. It was a thought turned on its side, a door left cracked in her mind. She was getting better at telling when she was doing it right.

A strange bird trilled high and off-key above her.

She thought-wished-longed-dreamt of leaves rustling.

Overhead, the trees shushed their leaves, forming vague, whispered words. Avide audimus.

She thought of a spring flower. A lily, blue, like her name.

A blue petal fell aimlessly into her hair. Another dropped onto the back of her hand, slipping down her wrist like a kiss.

Gansey’s eyes opened as petals landed lightly on his cheeks. As his lips parted, ever-wondering, a petal landed directly on his mouth. Adam craned his head back to watch the floral, fragrant rain drift down around them, slow-motion butterflies of blue.

Blue’s heart exploded with furious joy.

It’s real, it’s real, it’s real —

Ronan looked at Blue, eyes narrowed. She didn’t look away.

This was a game she sometimes played with Ronan Lynch: Who would look away first?

It was always a draw.

He had changed over the summer, and now Blue felt less unequal in the group. Not because she knew Ronan any better — but because she felt as if maybe Gansey and Adam now knew him less. He challenged them all to learn him again.

Gansey pushed himself up onto his elbows; petals tumbled from him as if he had been awoken from a long sleep. “Okay. I think it’s time. Lynch?”

Rising, Ronan went to stand starkly beside his mother and brother; Matthew, who had been waving his arms like a performing bear, stilled. Aurora petted Ronan’s hand, which Ronan permitted.

“Up,” he said to Matthew. “Time to go.”

Aurora smiled gently at her sons. She would stay here, in Cabeswater, doing whatever dreams did when no one was there to see them. It was unsurprising to Blue that she would fall into an instant sleep if she left the forest; it was impossible to imagine Aurora existing in the real world. More impossible still to imagine growing up with a mother like her.

My mother wouldn’t just leave forever. Right?

Ronan put his hands on either side of Matthew’s head, crushing the blond curls down, locking his brother’s gaze on his.

“Go wait in the car,” he said. “If we aren’t back by nine, call Blue’s house.”

Matthew’s expression was pleasant and unafraid. His eyes were the same color blue as Ronan’s but infinitely more innocent. “How will I know the number?”

Ronan continued to clasp his brother’s head. “Matthew. Focus. We talked about this. I want you to think. You tell me: How will you know the number?”

His younger brother laughed a little and patted his pocket. “Oh, right. It’s programmed in your phone. I remember now.”

“I’ll stay with him,” Noah offered at once.

“Chicken,” said Ronan ungratefully.

“Lynch,” said Gansey. “That’s a good idea, Noah, if you’re feeling up for it.”

Noah, as a ghost, required outside energy to stay visible. Both Blue and the ley line were powerful spiritual batteries; waiting in the car parked nearby should have been more than enough. But sometimes it wasn’t the energy that failed Noah — it was his courage.

“He’ll be a champ,” Blue said, punching Noah’s arm lightly.

“I’ll be a champ,” repeated Noah.

The forest waited, listening, rustling. The edge of the sky was grayer than the blue directly overhead, like Cabeswater’s attention was so tightly focused on them that the real world was now able to intrude.

At the cave mouth, Gansey said, “De fumo in flammam.”

“From the smoke into the fire,” Adam translated for Blue.

The cave. The cave.

Everything in Cabeswater was magical, but the cave was unusual because it hadn’t existed when they had first discovered the forest. Or maybe it had existed, but in a different place.

Gansey said, “Equipment check.”

Blue dumped out the contents of her ragged backpack. A helmet (bicycle, used), knee pads (roller skating, used), and flashlight (miniature, used) rolled out, along with a pink switchblade. As she began to apply all of these things to her body, Gansey emptied his messenger bag beside her. His contained a helmet (caving, used), knee pads (caving, used), and a flashlight (Maglite, used), along with several lengths of new rope, a harness, and a selection of bolt anchors and metal carabiners.

Both Blue and Adam stared at the used equipment. It seemed impossible that Richard Campbell Gansey III would have thought to buy anything less than brand-new.

Unaware of their attention, Gansey effortlessly tied a carabiner to a rope by way of an accomplished knot.

Blue got it a moment before Adam did. The equipment was used because Gansey had used it.

It was hard to remember, sometimes, that he’d lived a life before they’d met him.

Gansey began to unwind a longer safety cable. “What we talked about. We’re tied together, three tugs if you are alarmed in the slightest. Time check?”

Adam checked his battered watch. “My watch isn’t working.”

Ronan checked his expensive black one and shook his head.

Although this was not unexpected, Blue was still disconcerted, a kite cut free.

Gansey frowned as if he shared her thoughts. “Nor is my phone. Okay, Ronan.”

As Ronan shouted some Latin into the air, Adam whispered the translation to Blue: “Is it safe for us to go in?”

And is my mother still in there?

The reply came in the form of hissing leaves and guttural scraping, wilder than the voices Blue had heard earlier. “Greywaren semper est incorruptus.”

“Always safe,” Gansey translated quickly, eager to prove that he wasn’t entirely useless when it came to Latin. “The Greywaren is always safe.”

The Greywaren was Ronan. Whatever they were to this forest, Ronan was more to it.

Adam mused, “Incorruptus. I never thought anyone would use that word to describe Lynch.”

Ronan looked as pleased as a pit viper ever could.

What do you want from us? Blue wondered as they stepped inside. How do you see us? Just four teens sneaking into an ancient forest.

An oddly quiet earth-room lay just inside the cave entrance. The walls were dust and rock, roots and chalk, everything the color of Adam’s hair and skin. Blue touched a reluctantly curled fern, the last foliage before the sunlight faded. Adam turned his head, listening, but there was only the muffled, ordinary sound of their footsteps.

Gansey turned on his headlamp. It barely penetrated the darkness of the narrowing tunnel.

One of the boys was shivering a little. Blue didn’t know if it was Adam or Ronan, but she felt the cable trembling at her belt.

“I wish we’d brought Noah after all,” Gansey said abruptly. “In we go. Ronan, don’t forget to set the directional markers as we go. We’re counting on you. Don’t just stare at me. Nod like you understand. Good. You know what? Give them to Jane.”

“What?” Ronan sounded betrayed.

Blue accepted the markers — round, plastic disks with arrows drawn on them. She hadn’t realized how nervous she was until she had them in her hands; it felt good to have something concrete to do.

“I want you to whistle or hum or sing, Ronan, and keep track of time,” Gansey said.

“You have got to be shitting me,” Ronan replied. “Me.”

Gansey peered down the tunnel. “I know you know a lot of songs all the way through, and can do them the same speed and length every time. Because you had to memorize all of those tunes for the Irish music competitions.”

Blue and Adam exchanged a delighted look. The only thing more pleasing than seeing Ronan singled out was seeing him singled out and forced to repeatedly sing an Irish jig.

“Piss up a rope,” Ronan said.

Gansey, unoffended, waited.

Ronan shook his head, but then, with a wicked smile, he began to sing, “Squash one, squash two, s—”

“Not that one,” both Adam and Gansey said.

“I’m not listening to that for three hours,” Adam said.

Gansey pointed at Ronan until he began to breathily whistle a jaunty reel.

And they went in deeper.

Deeper.

The sun vanished. Roots gave way to stalactites. The air smelled damp and familiar. The walls shimmered like something living. From time to time, Blue and the others had to shuffle through pools and streams — the narrow, uneven path had been carved by water, and the water was still doing that work.