A VOICE BOOMED IN SOPHIE’S EAR. “GOOD MORNING, Damsel! Or perhaps it’s afternoon. Difficult to tell in this cave of yours.”

Sophie pried her eyes open, and the winged pony blew air in her face.

Sophie’s eyes watered. The pony’s breath smelled like overripe strawberries. Slowly, as if swimming to the surface of the ocean, her brain woke, and she realized she was back in the Dream Shop. “It worked! You’re here!”

“Of course I am. You are a damsel in distress, and I am supremely heroic. But before we begin our quest, I have a few complaints: I can’t see the sun, the clouds are much too firm under my hooves”—he pranced, demonstrating, and his hooves rang like chimes—“and lastly, it . . . well, not to be rude, but quite frankly, this place smells. I think that’s because it’s infested with monsters.”

Sophie shot up to sitting.

Beside the winged pony, Monster waved hello with his tentacles. Sophie relaxed. “That’s my friend Monster.” She pointed at Monster, then Ethan. “And that’s Ethan. And my name’s Sophie, not Damsel.”

Eyes wide, a dazed Ethan raised his hand. “Uh, hi.”

“Humph,” the pony sniffed. “And that one?”

From beside the somnium, a man slinked out of the shadows. He had no eyes or nose, and when he opened his mouth, it stretched so wide that the skin curled back to where his ears should have been. Jumping to her feet, Sophie cried, “Watch out!”

The eyeless man inhaled, and the bottles tumbled from the shelves and flew into his gaping maw. Other bottles across the room rattled together.

“Get a dreamcatcher!” Monster yelled as he launched himself toward the man’s legs.

Sophie threw herself at a counter and grabbed one of the nearly complete dreamcatchers. It lacked the feathers and ribbons, but the threads were all there. She clung to the counter as suction pulled at her. Her feet lifted off the ground.

“Sophie!” Monster released the man’s leg and wrapped his tentacles around her, trying to pull her down. He wrapped two tentacles around the distiller table leg to anchor himself.

Both of them were pulled toward the man’s overwide mouth, and Sophie felt her grip on the counter begin to slip. She screamed, and Ethan lunged for her. He grabbed her around the waist, and all three of them were lifted into the air.

Neighing as loudly as a trumpet, the winged pony charged from the opposite side. He pinned the man to the wall with his horn, piercing the man’s shirt collar, close to his throat. Abruptly, the man closed his mouth.

Sophie crashed to the floor. Scrambling forward, she pressed a dreamcatcher against him. “Move away,” she ordered the pony. “You can’t be touching him.”

The unicorn stepped back, and the man opened his mouth again. The wind howled in her face, but both Monster and Ethan held on to her ankles, anchoring her from below the gale. She felt the pull as if being sucked in by a tornado.

At last, the man faded and then disappeared. Sophie fell to her knees.

Releasing her, Ethan flopped onto his back. “What was that?” he panted.

“Not a nice monster,” Monster said. “Curious. Or perhaps not. Sophie, were you afraid of him in the dream?”

“Of the terrifying vacuum-mouth man? Gee, let me think . . . Yes, obviously.”

As if this satisfied him, Monster nodded. “So he came out as you expected him to. Like I did. You expected him to be terrifying, and he was. You expected me to be your friend, and I am.”

“But why did he come out at all? I didn’t want him to.”

“Perhaps he wanted to. My theory still holds. I chose to come out of the dream, and so did vacuum-man and the obnoxiously sparkly pony.”

Ethan rolled onto his side to look at Sophie. “Why did he disappear? What did you do?”

Sophie held up the dreamcatcher. “Changed him back into a dream.”

“But . . . how?”

“You need to hold the dreamcatcher onto the dream creature for long enough for it to dissolve back into a dream. A single touch won’t work, which is a good thing because otherwise, Monster would be in constant danger.” She wrapped her arms around Monster, and he squeezed tightly with all his tentacles.

“So, do you do this all the time?” Ethan’s voice was shaking, but she could tell he was trying to sound cool and unfazed. “Run around town, create and dissolve dreams, like some kind of superhero?”

Any second, he was going to bolt out of the shop screaming. Or lose it and start yelling at her. This was too much. Repression or not, he was going to freak out. “I’ve never done it before today,” Sophie said as soothingly as she could.

“If you’ve never done it, how did you know what to do?”

Monster fluffed his fur and stepped in front of Sophie. “Her parents told her how to do it, when they taught her how to destroy me. They thought she needed to know in case my monster tendencies got the better of me.” He bared his three rows of teeth.

Ethan backed up quickly. He thumped against the somnium table, and the glass tubes clinked as they bumped into one another. He jumped away from the table and then backed against a counter. “I didn’t mean . . . Sorry. This is just, you know, new to me.” His voice squeaked on the last word.

“And to me,” the pony put in. “Quite frankly, I always imagined my first quest would be in a more majestic location with much more savory companions. Perhaps it would be best if I returned to my dream.”

Sophie took a deep breath. It was too late for Ethan to flee or for the winged unicorn to change his mind. She’d already broken her most serious promise to her parents, and she was determined to see this through. She tried changing the subject. “What’s your name?” she asked the winged pony.

“Glitterhoof.”

Monster snorted.

Glitterhoof shot a look at Monster, then tossed his mane. Sparkles sprayed up in a cloud, dusting the Dream Shop in a fine layer of glitter. “It is an honorable and accurate name, Smelly Monster.”

“Just Monster,” Sophie corrected, trying to brush glitter off her shirt. It clung to her fingers. Ethan had glitter in his hair. Monster had dodged most of it.

Sliding closer to Sophie, Ethan said, “I’m sorry. Guess I didn’t really believe you before.” He lowered his voice to a whisper. “Just have a couple questions . . . Is he really . . . you know, real? Is he alive? Is he going to fade away? How long will he last? Will he go back to being a dream? When he’s in the dream, does he exist when no one’s dreaming him? Or is he, for all practical purposes, dead?” He lowered his voice on the last word.

“I’m right here, and I can hear you,” Glitterhoof said.

Ethan blushed bright red. “Sorry. It’s just . . . All this . . .” He raked his hand through his blond hair. “I mean, wow.”

Glitterhoof tossed his mane, shedding glitter again. “I understand your wish to know more. I am supremely interesting.”

Monster snorted again. “He also can’t answer you, because he doesn’t know. I can tell you that when I was a dream, that’s all there was. We exist within the dream, like characters exist inside a book. The dream doesn’t change, unless it’s dreamed again. Like a book rewritten. You feel safe inside your dream. You know you belong there.”

Sophie felt a little lurch in her heart. “You belong here, Monster.”

He patted her with a tentacle. “I know I do. But at first, it feels strange.”

She’d had no idea. He’d never said anything like this before. “Monster . . .” She didn’t know how to ask if he ever missed being in his dream. She wasn’t sure she wanted to hear the answer.

“As for how long he’ll last . . . Got me. I was told that I was an exceptionally vivid dream. The disco pony here, his dream was murkier. Who knows?”

“Again, you are discussing me while I am here. Highly rude.” Wrinkling his nose, Glitterhoof sniffed and turned to Sophie. “You promised a noble quest. There is nothing heroically grand about a musty old cave filled with grumpy monsters.”

“Right. Come on.” She stood and checked the clock. Her parents certainly should have been home for dinner. They always ate dinner together. Yet more proof that they were in danger, not merely out running an errand. She tried to shove the last of her doubts aside. It was too late for second, or third, thoughts. Leading the way, she stopped at the stairs. “Um, can you climb stairs?”

Folding his wings on his back, Glitterhoof glared at Sophie. “I am not a cow.”

“Yeah, I see that,” Ethan said.

“Cows can’t walk up stairs,” Monster explained. “Their knees are backward. Also, they’re stupid.”

“Precisely.” Tossing his mane, Glitterhoof marched on his four golden hooves up the stairs and then trotted through the bookshop. Craning his neck, he looked around the shop. He barely fit between the shelves. The tips of his wings brushed the spines of the books. “What are these things that clutter up your cloud?”

“Books,” Sophie said.

“What are ‘books’? Are they tasty?” Stopping, he nibbled at one, an old copy of Jane Eyre with a cloth spine.

Sophie rushed to stop him. “You don’t eat them! You read them. They’re written-down stories. You know stories?” Glitterhoof continued to chew, taking out a chunk of Pride and Prejudice. “Dreams! They’re like dreams. But dreams that you have while you’re awake.”

“Oh my!” Glitterhoof spat bits of paper out on the floor. One hit Sophie’s shoe, and she read the words “no compassion for my poor nerves.”

Monster scooted past them, heading for the back door. “Can we move along?”

Ethan followed. “Are we really going to ride that?”

“I am not a that,” Glitterhoof said. “I am a pegasus, direct descendant of Poseidon and foaled by the Gorgon Medusa during the moment in which Perseus decapitated her—which, by the way, was rude.” Swiveling his head, he fixed his sparkling eyes on Ethan. “You, on the other hand, are descended from dirt.”

“Monkeys, actually,” Monster corrected. Twisting the knob with a tentacle, he pushed the back door open. “And you were designed by a toy company.”

Glitterhoof slammed the door shut with his hoof.

Spinning around, Monster bared his teeth.

Sophie stepped between them. “Not now. Please, Monster. Glitterhoof, we’re honored to have the help of such a noble . . .” She hesitated, not sure what word wouldn’t offend him. She didn’t have a lot of practice flattering people. Or ponies. “I know this isn’t what you expected for your first quest, but there are people in danger, and we really do need your help. You could save the day.”

Mollified, Glitterhoof lowered his hoof from the door. “Very well. It is in my nature to be both heroic and magnanimous. Forgiveness is a hallmark of greatness.”

Shooting a warning look at Monster, Sophie turned to Ethan. “Ethan, can you show Glitterhoof the map so he knows where we’re going?”

“Oh, right.” Ethan pulled out his phone and showed the pegasus the map, switching it so it looked like an aerial view. After expressing amazement at the device, Glitterhoof studied the map.

Softly, Sophie said to Monster, “Try to be nice. He’s here to help.”

“He’s not physically possible,” Monster complained. “His wingspan cannot possibly support his body weight. A pigeon weighs about a pound, and its wingspan is a foot. Average horse weighs more than a thousand pounds. He’d need a thousand-foot wingspan. Besides, pegasi don’t have horns. He’s not a purebred pegasus; he’s a mutt. And he’s shedding glitter, which is weird.”

Sticking his nose in the air and studiously pretending he couldn’t hear Monster, Glitterhoof asked Sophie, “Would you prefer to travel by flight or rainbow?”

That wasn’t a question she’d ever been asked before. “Uh . . . flight?”

“Then climb onto my back. We will exit quickly and stealthily, and we will fly high above the clouds so we cannot be seen.” He knelt his front knees on the floor. Sophie climbed on first, and Monster jumped up into her lap. Ethan swung on behind her and wrapped his arms around Sophie’s waist. “Hold tight,” Glitterhoof commanded. “If you must vomit, please try to aim away from my glorious mane.”

“Can’t believe I promised not to tell anyone,” Ethan said. “This is awesome.”

“Yes, indeed. I am pure, unadulterated awesomeness, not a toy or a mutt. I am going to fly so fast that the humans will not be able to see us.” He bashed the door open, folded his wings tight to his sides to fit through, and squeezed out the opening. On the step, he paused as he gazed at the backyard with its aluminum shed, patchy lawn, and unweeded herb garden. “Ooh, so many colors!”

Sophie squeezed his mane. “Fly! Quickly!”

“My apologies, Damsel.” The pegasus launched into the air. His wings flapped, and all the stray twigs and leaves in the yard swirled into the air. He shot through the debris toward the sky.

Sophie felt her stomach plummet. Wind battered her face, and she had to squeeze her eyes closed. Monster dug his claws into her arm, and Ethan’s arms tightened around her waist. The wind sounded like a shriek. She felt water droplets batter her face.

Steadying, the pegasus flew straight and even. Sophie cracked her eyes open and looked down. Clouds streaked the view below them. Cars looked like toys between the houses. Roofs made a patchwork, and the streets looked like black rivers. Pointing past her face, Ethan shouted, “There! Left! Go left!”

Tilting, Glitterhoof dived to the left. Sophie clung to his mane. Monster’s fur was fully fluffed. His face was hidden in black fuzz.

Below, the park looked like it was made of green felt, and the playground was made of brightly colored toothpicks. Soon, they were soaring over curlicue neighborhoods with identical houses and abnormally green lawns. Each driveway had an SUV in it.

Sophie wished she could enjoy this. The dying sun felt warm on her back, and the wind blew in her face so hard that it felt like it wanted to blow away every worry, every fear, and every doubt she’d ever had—but it didn’t work. She couldn’t forget her parents were missing.

After the snarl of identical houses, the view changed again, and the houses were more spread out with thick clumps of trees. Sophie hadn’t realized they’d biked so far earlier.

“See that?” Ethan shouted over the wind. “Those trees! His house is the only one.”

From up here, Sophie could see that Mr. Nightmare had no neighbors. There were thick wooded areas on all sides, which made it a perfect isolated location for a kidnapper. She could also see he had an aboveground pool and a deck, which didn’t fit her image of a kidnapper. She wondered if she was wrong, for a second time. He could be 100 percent innocent, and she might be hoping too hard to see connections when there were none.

In front, tucked near the trees, were three cars: Mr. Nightmare’s blue car plus two others. Maybe he had friends over? Oh no, more people to avoid, she thought. That could make this harder—or, if they were lucky, easier. With luck, the friends would distract Mr. Nightmare, and he wouldn’t notice Sophie, Ethan, and Monster creeping around.

The pegasus spiraled down, circling the house. “There is a cave beside the dwelling. I will hide in it.” Without waiting for a response, Glitterhoof flattened his wings to his sides and plummeted. The ground raced toward them, and Sophie clutched his mane. Her fingers dug into her palms. Monster hissed at the wind, and Ethan pressed against her back, holding on as tightly as a seat belt.

Glitterhoof shot into Mr. Nightmare’s detached garage. He braked with his wings and landed gently. Even his hooves were silent on the concrete floor. “Speed and stealth.”

“Yeah, very impressive.” Monster slid off his back into a heap. On wobbling legs, he staggered away and then leaned against a lawn mower to pant. His tentacles hung as limp as cooked noodles. Sophie climbed off with Ethan. Her head was spinning, and she kept one hand on Glitterhoof’s neck to steady herself.

“Do I earn an extra apple for that landing?” Glitterhoof asked, hopeful.

Sophie patted his mane. “It was a wonderful landing. Thank you. Definitely an extra apple. And if you stay hidden and wait for us, you can have as many apples as you want.” She hoped she didn’t sound as nervous as she felt. She’d never sneaked into a house before. They’d have to be very, very careful.

Glitterhoof whinnied (quietly) in approval.

Sophie felt Monster looking at her as he licked his fur flat. “What?” she whispered.

“You bribed him with fruit.”

“So? He likes apples.”

Monster sauntered past Sophie to the entrance of the garage. “Not a problem. I’m just happy you didn’t tell him about the cupcakes.”

Behind them, Glitterhoof cried softly, “What cupcakes?”