Even at six, Dea knew that she was trespassing on something very private.

All at once the birds converged and became an enormous kite, so large it blotted out the sky. Then the court was swallowed in shadow and she knew it was time to wake up.

Outside the little pool house, it was raining. And for the first time in Dea’s life, her heart was beating normally.

Her mom knew what she’d done. At the time, Dea didn’t think that was strange. She was Mom. She knew everything. She knew how to make the perfect chicken soup by adding cream and tomato to a can of Campbell’s. She knew how to catch a single raindrop on her tongue. She knew mirrors and open water were bad, and clocks were good.

That day, Miriam sat at the kitchen table, gripping a mug of tea so tightly Dea could see individual veins in her hand, and explained the rules of walking.

The first rule, which Dea had already intuited, was that she must never try to change anything or intervene in another person’s dream.

The second rule, related to the first, was that she might walk as many dreams as she wished if she was careful, and followed all the rules, but she must never walk the same person’s dreams more than once.

And the third rule was that she must never, ever be seen.

Her mother explained other things, too—that birds were harbingers and would serve as guides, that mirrors and water were places where the boundary between the worlds was the thinnest, that clocks would keep them safe from the other side—but Dea had barely listened, so disappointed was she by the list of rules, especially the fact that she was forbidden from entering Mira’s dreams again.

“Why can’t I go back?” Dea had asked.

Dea’s mom reached out and took Dea’s chin. “I won’t let them find you,” she said. Her eyes were very wide; she was looking at Dea as if trying to beam a secret message to her, and Dea knew her mom was afraid.

Then Dea was afraid. “Who?” she asked, although she felt she already knew the answer.

“The monsters,” Miriam said simply.

THREE

At six o’clock and every six hours afterward, even on Saturday, the clocks started. First a half dozen, then a few more, then a handful more. Dea and her mom had more than two dozen clocks, at last count, many of them fitted with chimes and bells, gongs and whistles. Miriam liked them, said they comforted her. She liked how they pulled her into morning with a song of gears and mechanics.

Dea was used to them. The clocks had come with them to all the houses they’d lived in. Often, Dea managed to sleep through them. Today she was jerked awake and, for one confused second, couldn’t remember where she was, which house, in which town, in which part of the country. As soon as the last clock stopped chattering, she rolled over, pulled the sheet over her head, and went back to sleep: deep and dreamless, like always. Like how she imagined it would be to swim, to sink into dark water.

When she woke up again, sun was streaming through the paper blinds. It was after eleven a.m. She could hear her mom padding around the kitchen downstairs. She loved that about this house: the space, the sense of separation. She hated Fielding, and missed living in cities like Chicago and even Houston—but there they’d lived on top of each other, sometimes sharing a single bedroom.

She pulled on clothes without paying attention to what she was wearing, then moved to the closet and extracted a small mirror from behind the jumble of sneakers and boots and flip-flops worn down to paper. Her mom allowed absolutely no mirrors in the house. Whenever they moved, the first thing Miriam did was dismantle the bathroom cabinets. Dea had a growing collection of forbidden mirrors, all purchased from yard sales: tarnished silver handhelds, makeup compacts obscured with a thick coat of ancient powder. Sometime in the spring she’d told Gollum in passing that she collected mirrors, and for Dea’s birthday Gollum had presented her with a pretty chrome handheld, obviously antique, so heavy it hurt Dea’s bicep to lift it. Dea had nearly cried, especially since she knew Gollum’s family had hardly any money.

“Don’t worry,” Gollum had said, in that ridiculous way she had of being able to read Dea’s mind. “I stole it.”

She was kidding, obviously. Dea was embarrassed and humbled by Gollum’s generosity, especially since for Gollum’s birthday Dea had just gotten her a leopard-print Snuggie (to be fair, Gollum was obsessed with Snuggies, or at least the idea of them). The chrome mirror, along with the picture of her father displayed in the living room, was one of the few physical possessions she actually cared about.

She checked her reflection. Hair: enormous. Skin: clear. Her one good feature. Eyes: pale blue, the color of ice. She made a monster face, then put away the mirror.

“Feeling better?” her mother said, as soon as she came downstairs. As usual, Miriam could tell that Dea had walked.

“A little.” Dea nudged Toby out of the way and moved toward the coffeepot.

A week earlier she’d pocketed a cheap plastic hair clip Shawna McGregor had left on a bench after gym. She knew it would be difficult to use—the best doorway objects were the ones that were cherished and closely guarded, like jewelry or wallets. Her mom speculated that it had something to do with the way that the mind transforms the objects we love best into extensions of the body. Touching someone’s favorite necklace was nearly as good as holding hands—and made it so much easier to get in.

The night before, she’d had to grip the hair clip for nearly an hour before she could push her way into Shawna’s dream.

She’d been in and out relatively quickly, before the dream had time to change. It was a dream of a standard basement party, the kind of gathering that Dea had never experienced in real life—lots of sweat and bodies packed close and plastic cups, as boring as she’d always imagined parties like that would be, filled not just with the standard assortment of high school kids but also with strangers, including a boy who looked like he’d stepped out of a fairy tale. Maybe he had. Maybe he was Shawna’s Prince Charming.

Hanging back behind one of the walls of the overstructure—a decaying castle hung with moth-eaten tapestries and pictureless frames—Dea had watched him, drawn to him without exactly knowing why. His hair was a dark tangle and fell to his jaw. He was tan, as if he’d spent a long time in the sun, and wearing strange clothes and an old-fashioned belt fitted with a knife. And while everyone else was dancing to an inaudible current of music, he was perfectly still—observing, just like Dea was, as if somehow the rules of Shawna’s imagination didn’t apply to him.

Then, suddenly, he started to turn toward her. Dea had ducked quickly away.

Dea’s mom came over and gave her a squeeze. Even through layers of clothing, Dea could feel how thin her mom was.

“What about you?” Dea said.

“I’m fine.” Miriam pulled away and reached for the coffeepot.

“You look tired.” Miriam looked worse than tired, but Dea didn’t want to say so. Her skin was so pale, Dea could see individual veins running through her wrists and neck. Her eyes—big and beautiful, the color of storm clouds—looked huge in the narrow hollow of her face.

Dea’s mother walked dreams too. Dea had known that since she had known what walking dreams was, but Miriam hardly spoke of it except in generalities. Dea had asked her once whether her grandparents had walked too, thinking it might be some genetic aberration. But Miriam just said no and Dea didn’t press it. That was another thing they hardly ever spoke about: family, or why they didn’t have any, and where they’d all gone.

The single picture of her father, positioned prominently on top of the living room mantel, was a snapshot from probably twenty years earlier, when he was young and wearing a cheesy red polo shirt and laughing, petting a dog. She didn’t know if it was his dog or her mom’s, or when the photo was taken, or where. In some ways she didn’t like to ask, because then it would ruin her ability to imagine.