THE SUN WASN’T AWAKE YET, THOUGH SOPHIE WAS. Sitting up, she poked Monster with her foot. Per usual, he’d crawled up onto her bed during the night. He claimed he did it in his sleep. He was now a warm weight at the foot of the bed. “Hey! Wake up!”

Groaning, Monster flopped his tentacles over his head.

“It’s morning!”

“Not morning.”

“Almost morning, sort of.” Lifting the shade a few inches, Sophie peeked outside. The streetlights were still on, but the sky had that expectant, about-to-brighten look. The stars were pale, and the moon was fading. She let the shade flop down again so no one could see inside, and she flipped on the light.

“Gah!” Monster cried. “I’m blinded!” He waved all his tentacles in the air.

She threw a pillow at him. “Stop it. Mom and Dad said we could sort the new dreams before school if we woke extra early, remember? Special birthday treat.” Having a dream shop meant keeping odd hours. You couldn’t risk ordinary book customers finding out about it, so most of the work had to happen before dawn or late at night. Sophie was used to waking up hours before the bus came. Monster always whined, though.

He opened one eye. “Do you think there will be more wolf dreams? I like those.”

Wolf dreams usually featured exciting chase scenes through dark woods. Sophie liked them too, except when they ended with munching on a rabbit. She’d always had a soft spot for rabbits. “Maybe there will be mermaid dreams.”

Sitting up, Monster licked his fur clean like a cat. He had a golden tongue. “I do not understand why anyone would want to be half fish. Eat fish, yes. Be a fish . . . no.”

“You could swim with dolphins.”

“If you want to swim with dolphins, then be a dolphin. At least then you’ll still be a mammal instead of half mammal and half mackerel.”

“But mermaids sing catchy songs about seaweed.”

“Technically, the crab sings; the mermaid is an unwilling audience.” Snagging Sophie’s hairbrush with a tentacle, Monster pretended it was a microphone and whisper-sang “Under the Sea.” Sophie drummed in the air, silently so her parents wouldn’t hear. In the middle of a lyric about a fish on a plate, Monster’s stomach growled, and he broke off singing. “Speaking of special birthday treats . . . cupcakes for breakfast?” Monster widened his eyes hopefully.

Ms. Lee had baked a fresh batch in honor of Sophie’s birthday. Imagining them, Sophie could practically taste the frosting. They never got to eat them fresh, but today was a special day, and they were baked in her honor . . . “Mom and Dad won’t like it . . .”

Monster inched toward the bedroom door. “There might be some with pink frosting. And sprinkles. Special birthday sprinkles. Mmm.”

Lunging forward, she caught him around the waist. “I’ll get them.”

He wiggled free. “I will be sneaky. I am the sneakiest monster. I did your homework for you last night, and you didn’t even notice. Special birthday surprise!”

“Uh-oh.” Releasing him, Sophie crossed to her backpack. She’d intended to do it on the bus. It kept the other kids from talking to her.

“Why ‘uh-oh’?” He bounded after her.

“Last time you wrote every letter upside down. I had to claim it was an artistic experiment.” She pulled out her homework. He hadn’t touched history, but her science worksheet was complete. She scanned it. Instead of drawing a plant cell, Monster had drawn in minute detail the circulatory system of a rodent. He’d also answered every multiple choice question with C. “Oh, Monster.”

“Cupcake?” He wagged his tentacles like a dog with six tails.

She gave up. “Stay,” she ordered.

Unlocking her bedroom door, she sneaked past her parents’ room and down the stairs. She knew exactly which boards squeaked, and she eased over them, gingerly placing toe first and then heel as she crept down two flights to the bookshop.

There, on the counter, under a glass dome lid, was the tray of cupcakes. It was near the window, and light from the street lamp shone in, illuminating the tray as if it were in a spotlight. She crossed to it and lifted the lid.

Behind her, the bell over the door rang.

She froze.

“Good morning.” A voice drifted over the bookshelves. It was male, smooth, and deep. She thought she heard a hint of an accent, maybe British. She liked accents. When people with accents came into the shop, she often hid between the bookshelves and eavesdropped. People with accents tended to know different stories and have different dreams. But nice voice or not, it was too early for customers. The door should have been locked.

She thought about pretending she wasn’t here, but she couldn’t just leave him wandering freely. She wished her parents were downstairs. “I’m sorry, but we’re not open yet.” Craning her neck, she tried to see him around the bookshelves without him seeing her. The door had already swung shut, and he wasn’t in view.

“My apologies. I’m early for my appointment. Please convey to the owners of this establishment that I’m here to make a purchase from their downstairs collection.”

Oh no, Sophie thought. This was a dream buyer. She wasn’t supposed to talk to buyers or suppliers. In fact, they weren’t even supposed to know she lived here. Her parents had a system to avoid situations like this. Every morning as she packed her lunch, Sophie was supposed to check the calendar on the refrigerator. Days she had to hide herself and Monster were marked in black, and days she had to take the recycling out to the curb were marked in green. Today, she hadn’t gone to the kitchen to check the calendar. “I’m Betty from next door. But I’m sure I can find them for you.”

“Very well, Betty from Next Door.”

She bolted toward the stairs. As she did, she saw the buyer sit in one of the red velvet chairs by the bay window. He wore a hat that shaded his eyes so that they looked like black smudges. His chin had a tiny beard, the kind that is as meticulously trimmed as if it were a topiary. He wore a trench coat and carried a briefcase. Except for the fact that she couldn’t really see his eyes, he didn’t look so scary. He looked like countless others who came into the shop looking for books.

She met her mother halfway across the shop. Mom frowned at her. “Sophie, you should be upstairs. We’re expecting a buyer in about fifteen minutes. I’ve already unlocked the door for him. Didn’t you check the calendar?”

Sophie wished Mom had spoken softer. She was certain that the man had heard her name wasn’t Betty. Also, he could now guess that she belonged here. “He’s here.”

Mom’s face whitened. Her lips pursed tight. “Go.”

Sophie fled toward the stairs as she heard Monster cry, “Sophie, come back! The calendar’s marked black. It’s not safe!” A streak of fur sailed over the books. He collided with her stomach, and she was propelled backward. They smacked into a bookshelf. Books flew off the shelf and crashed down on either side of them. Monster shielded her from them, and several smacked into his back.

“Sophie! Are you okay?” Mom rushed toward her.

The man in the trench coat approached as well.

“He’s the buyer,” Sophie whispered to Monster. He twisted his neck to look at Sophie’s mother and the man. His lemur eyes opened impossibly wide, and then he bounded toward the stairs. His tentacles pawed the floor, propelling him faster. In seconds, he was out of sight.

The man in the trench coat watched it all.

“I’m fine,” Sophie said. “Just . . . my cat. He loves to cuddle.”

Kneeling, the man picked up several books. He handed the stack to Sophie. “Unusual cat, Betty.”

Sophie forced a laugh. “He’s . . .”

“Mutation,” Mom interrupted. “Owners were going to have him put down. But other than the extra appendages, he was perfectly healthy. If you’ll follow me downstairs, please . . . ?”

“Of course.” The man didn’t take his eyes off Sophie as he passed her. She froze and wished she could melt into the bookshelf. Her rib cage felt tight, as if it were squeezing her lungs. Closer, she could now see the man’s eyes, and she preferred when they were shadowed. The whites were streaked with red as if he hadn’t slept in days, and the skin underneath them sagged into wrinkled pouches. He tipped his hat toward her, and then he followed her mother downstairs.

Monster poked his head around the corner of the stairs. “Sophie?”

“It’s safe now,” Sophie said. “I think.”

“I failed you,” Monster said.

“It was an accident.”

All six tentacles drooped. He slunk down the stairs to curl around her ankles. “I’m supposed to protect you.”

She scooped him into her arms, staggering back from the weight. “Don’t blame yourself. I’m the one who forgot to check. It’s my fault. I’ll tell them they shouldn’t yell at you.”

“I don’t care if they yell or yodel; I just want you safe.”

But her parents didn’t yell at either of them. In fact, they didn’t speak to them at all. After the buyer left, they retreated back down to the basement, shutting the door behind them. Monster pressed his ear to the door. Sophie tried to hear through the crack beneath it.

“. . . like Abril’s farm.” Mom’s voice drifted up the stairs and through the door. “It’s a good place for a girl to grow up. Chickens and so forth. Streams to jump in. Fresh air. Lousy school district, but Sophie is smart enough on her own.”

“It may not be a problem,” Dad said soothingly.

“He saw Monster! There was no disguising him. Or Monster’s connection to Sophie. It was clear he belongs to her.”

“But it is unlikely he’ll guess Monster’s origin,” Dad said. “More likely, he’ll think we found Monster. Or bought him. There’s no reason for him to assume—”

“And what if he does? Are you willing to take that risk? With Sophie? If he tells the Night Watchmen . . . I don’t know what they’ll do if they find out about her, and I don’t want to ever find out.”

“Why would he? He’d have to admit he was here and why.”

“But what if the Watchmen—” Mom cut herself off, then said loudly and clearly, “Sophie and Monster, if you are up there listening by the door, I will revoke all book privileges so fast, you will have whiplash.”

Sophie and Monster scrambled away from the door.

“Get ready for school. Upstairs, both of you. Now.”

Sophie and Monster ran upstairs.

Monster took the steps three at a time, reaching with his tentacles, and Sophie bounded behind him, up to the living room and all the way up to the bedrooms. She slammed her bedroom door shut. She then dived onto her bed and wrapped her blankets around her. Monster curled against her back.

“Do you think he’ll tell the Night Watchmen about me?” Sophie asked.

“He’d have to admit he was buying dreams,” Monster pointed out. “The Watchmen won’t like that. Plus if he tells, the Watchmen will come and destroy the shop, and he’ll lose his source of dreams.”

“Not helpful, Monster.” Her eyes felt hot. She was going to cry. She hated crying. It made her insides feel squishy, like she’d swallowed a jellyfish and it had lodged itself in her throat. All her life she’d heard about the Night Watchmen—“vigilantes,” Dad called them. Really dangerous, really organized, really determined fanatics who wanted to stamp out the dream trade and anything to do with bottled dreams. If she could have nightmares, they’d be star players. “Do you think Mom and Dad will really send me away?”

“They’re scared for you, as am I,” Monster said.

“I don’t want to live on a farm,” Sophie said. “I want to stay here!”

“Me too.” His voice was tiny, as if he’d shrunk.

She twisted to look at him. She realized she hadn’t heard them say “Sophie and Monster.” They might not intend to send Monster with her. They could decide it’s too risky. He’d hidden every time Aunt Abril had come to visit, and he’d stayed home the one time they’d visited her. By the time they got back, he’d eaten all the food in the refrigerator, plus a few forks and plates. “You’ll come with me if I go, won’t you?”

“I go wherever you go—to the ends of the earth, even if that phrase doesn’t make any sense because the earth is round,” he said. “You’re my friend.”

“You’re my best friend,” Sophie said.

“My best friend,” Monster repeated. He laid his snout on her shoulder and purred.

Throwing her arms around him, she said into his fur, “And this is officially the worst birthday ever.”

“I didn’t even eat any cupcakes,” he said mournfully.

She laughed—a tiny, barely there laugh, but it still counted.

Outside, the sun began to rise. Yellow light seeped in around the shades and streamed through the skylights. Sophie dressed slowly, brushed her teeth, and tied her hair back into a ponytail. As she was finishing, her dad called up the stairs, “Sophie? Monster? You can come downstairs now.”

She and Monster looked at each other. He kneaded the carpet with his claws, nervous. Neither of them said anything as they headed down to the Dream Shop.

She found her parents by the somnium. Quietly, she tucked herself under the stairs beside them. Dad poured a bottle of shimmering yellow into the silver funnel at the top. The liquid dream dribbled down the tube, lighting up the glass with a soft glow. It twisted and stretched as the tubes narrowed and turned, forcing the dream to lengthen and separate. At last, the dream slid into the glass chamber at the heart of the somnium, where it dispersed in the steamlike solution. All four of them pressed their faces closer to the glass.

“Get the bingo cards, Sophie,” Dad said without looking at her.

Sophie raced to a drawer and pulled out the cards. They’d invented their own bingo game a few years ago. Each square showed a different theme or event or object commonly seen in dreams. Get five in a row and you won. She handed her parents their cards, and one to Monster. Several squares were already marked off from last time.

Maybe they aren’t going to send me away, she thought. Maybe they changed their minds. She waited for them to say anything, but they merely watched the somnium. Slowly, an image materialized.

It was a girl. Sophie squinted at her. She thought she maybe recognized her, perhaps from school? She wasn’t sure. It was difficult to see the girl’s face as she swooped between the mists of the somnium as if they were puffs of clouds.

“A flying dream,” Dad said. He checked his card. “Nope.”

“Got it,” Mom said. She marked a square on her card.

From the bottom of the somnium, waves of blue lapped at the glass. Sophie pointed at a loglike shape that surfaced. It was covered in bumps. It opened its jaws. “Crocodile,” she said. She checked her card for wild animals. She had a square for pets but none for predators.

The girl screamed, her mouth wide but the scream silent in the glass tubes. There was never any sound in the somnium. She plummeted through the darkening clouds toward the crocodile-infested water.

“I have falling!” Sophie said. “Oh, wait, got that already.”

Before the girl could smash into the water, she landed in a pile of leaves. A circle of kids stood around her, laughing and pointing. The girl curled into a ball.

“Highly generic dream,” Mom observed.

“I have humiliation.” Dad peeked at their cards. “Better watch out. I might win this round.” He sounded like himself. Was neither of them going to mention the buyer? She wasn’t sure she dared ask, but she couldn’t stand not knowing. Not knowing felt like being pricked with a dozen needles.

“I already have three in a row.” Sophie held up her card for them to see.

Dad held up his. “Three on a diagonal, plus the free space in the center. I only need”—he checked the square—“a historical anachronism.”

Sophie wrinkled her nose. “What’s that?”

“It is a contradiction in times,” Monster said. He had chewed his own card to shreds. “For example, a phone rings in medieval England. Or a knight jousts in Times Square. Something that doesn’t belong.”

Taking a deep breath, Sophie said, “I don’t belong on a farm.”

Mom and Dad exchanged glances.

“We know,” Dad said quietly. “You belong with us.”

Sophie hugged her parents, and Monster wrapped his tentacles around them all.