The woman shut the box. “I know the song. But I did not wish to hear it.”

“It plays what you need to hear, not what you want to hear.”

The woman’s eyes glittered. She ordered her footman out of the shop. Then she paid much more than the asking price for the Muse Box. She gripped the box in both hands as she left the Sign of the Compass.

That evening, when Petra bid her father good night, she hugged him and said, “You know I love you very much.”

“I do know that,” he said, and placed his wrinkled hand on her knotted hair.

“Do you know … did you hear that it rained sand last week? With thunder and lightning? On a clear day?”

“Did it?” His voice was indifferent, but in a practiced way.

She whispered, “Aren’t you worried?”

He paused, and Petra saw that he was. Still, he tried to persuade his daughter that everything was all right. “If the prince caused this, it only means that he cannot control the clock’s power. Perhaps he has been able to assemble the last part to some degree. That is possible. Lightning would be the easiest thing for the clock to produce. But I never designed the clock to rain sand. This suggests to me that he cannot assemble the last part properly.”

“But he’s trying.”

“Petra.” Her father’s voice was stern as he gripped her shoulders. “The clock is no longer our concern. Do you understand?”

“Yes.” His white bandages confronted her. She nodded, although she knew he could not see her. “I do.”

8

Firefly

A FEW DAYS LATER, when Petra was visiting Tomik at the Sign of Fire, he hissed at her so Master Stakan wouldn’t hear: “Lucie and Pavel leave tomorrow morning. Dawn. I’ll be there.”

Petra practically ran home.

Through the twilight, she saw the sign with a compass that looked like a flower transformed into a machine, or a machine transformed into a flower. Petra veered. She sprinted around the house to the back. She took off her shoes and loped through Dita’s small garden.

Petra had avoided coming here. Not because of Dita’s rows of green plants, but because of the building not far from them. It was her father’s smithy, with its forge and a water-filled slack tub for cooling red-hot iron. A little over a month ago, the sight of the smithy would have been disheartening. But tonight her mind burned as brightly with excitement as any piece of fire-tempered metal. Ever since Astrophil had suggested that her father had lost his sight while trying to secure a noblewoman’s education for her, Petra felt a heavy guilt. She wanted to turn that feeling into the glow of pride.

For twelve years, she had not been what the villagers might call an impressive girl. Petra attended classes at the schoolhouse, but found them dreadfully boring, and received average marks. She was lean, not exactly pretty—she had high, wide cheekbones and the odd silver eyes of her father. Mikal Kronos always claimed she had a knack for metalworking, but she’d never really applied herself to learning what he could do. Now that she was old enough to become her father’s apprentice, and at least learn the more ordinary aspects of his trade, there was so much that he was unable to do, unable to show her.

But these things would change.

Petra entered through the back door. She went to the library and scooped a protesting Astrophil off the pages of a book about geometry. Then she walked into her bedroom, shut the door behind her, and raised her right palm to face the flustered spider.

“Time for bed,” she announced. “We’re leaving tomorrow. Will you wake me two hours before dawn?”

He didn’t reply at first. Then he said slowly, “Your plan to go to Prague is brave, Petra, but is it wise?”

“What could happen to us? We’ll be with Lucie and Pavel. Besides, we’re just going to explore the option of rescuing Father’s eyes. This will be a preliminary investigation. You know I wouldn’t do anything dangerous.”

If Astrophil had eyebrows, he would have raised them in disbelief. “This adventure could be like a riptide.”

“What do you mean?”

“A riptide is when you swim in the sea, close to the shore, never intending to go out very far, and then an underwater current sucks you out far into the deep water.”

“How poetically grim of you, Astrophil. First of all, Bohemia is landlocked, remember? We have no seas. So we’ve nothing to fear from riptides.”

“You are deliberately misunderstanding me.”

“And second, you’re forgetting just how much we can learn from this experience.”

The spider noticed which word she had stressed. “You are deliberately tempting me.”

“Think about everything that Prague has to offer. The most learned scholars in Bohemia live there. And what about the prince’s library? Wouldn’t you like to at least see it?”

The spider was quiet, thinking. Then he said, “I suppose that someone must look after you.”

“Four o’clock in the morning, then?” Petra said cheerfully.

“If you actually manage to get out of bed at four o’clock, I will eat my spiderweb.”

Petra pulled a thick burlap sack from a drawer and filled it with a jug of brassica oil, the little wooden box containing Astrophil’s spoon, a knife, two pairs of trousers, three drawstring shirts, and a work smock. With a grimace, she added a brown skirt that was stiff from having never been worn. She thought a moment, and then tossed in clothes for winter: a hard leather coat and a woolen scarf Dita had knitted for her. Pavel and Lucie might not stay long in Prague. But that didn’t mean she had to leave the city with them.

She blew out the candle. She would pack the rest of what she needed in the early morning, when she was less likely to draw the attention of the rest of her family. David, she was sure, was still awake in his room on the top floor, above hers.

Petra struggled to fall asleep. She thought of how happy her father would be when she returned with his stolen eyes. She would suggest new tin pets to craft, like a firefly. She imagined a green light blinking on, off, on, off, and on again, until finally everything was dark and she slept.

ASTROPHIL HAD TO PINCH her several times before she sat up. “Ow! Astro! Is that really necessary?”

“Perhaps. Perhaps not. But it is entertaining.”

Petra dragged on her clothes, still sleepy. She took a sheet of paper down from a shelf, along with a goose quill and a pot of ink. She forged the note from Dita to Lucie and Pavel. She blew the ink dry. Then Petra ripped a scrap from the empty bottom of the page, and tucked the forged letter in her bag. Inking her quill, Petra bent over her desk again. On the scrap of paper she wrote:

Dear Father, Dita, Josef, and David,

I’ll be back soon. Don’t worry about me.

Love,

Petra

Petra shouldered her packed bag. She softly stole across the hall to her father’s library, then began riffling through books and papers.

“What are you doing, precisely?” asked Astrophil.

“Looking for drawings or notes about the clock,” she replied. Her father’s loss was connected to the clock, and she needed to have as much information about it as possible.

When false dawn began to brighten the library, filling it with the gray light that comes just before the sun rises, Petra gave up. Her father must have left any papers about the clock in Prague, probably in the hands of the prince.

There was one thing left for her to do. She unlocked the safe in the floor and took some krona —not much. Then she resealed the secret compartment.

She was ready to leave the room when something about the floor caught her attention. In the smooth wooden board hiding the safe she saw the pattern of extremely tiny holes. She wondered why she had never noticed them before. Perhaps they could be seen only by dawn light. Certainly she had never been awake this early to gaze at the floor of her father’s study —or to do anything at all, for that matter.

“Ahem.” Astrophil tapped one leg impatiently.

Petra ignored him. She inspected the floor more carefully. She noticed a dusty rug at the foot of one of the bookshelves. She pulled it aside and saw, to her excitement, a constellation of holes smaller than the point of a needle bored into the gleaming wood.

She climbed up the ladder to the dandelion for the second time, her heart beating. Shifting aside a book on water fountains, she blew once on the flower. The seeds did not budge. She shook the stem, but it simply bent back and forth without shedding any of its seeds. Nothing worked.

Astrophil said, “Again I must ask: what are you doing?”

“I’m not sure,” she admitted. Petra glared at the dandelion. She felt like shaking it again just to relieve her frustration, but instead she pushed the book back into place.

But as she did so, something occurred to her. Nestled next to the book on water fountains was another one about precious stones. She gnawed her lip in anxious consideration, and then uncovered the dandelion again, taking in its round, silver shape.

“Petra, do you want to go or not? Because we need to leave now”

She leaned toward the flower. Then she said, “Marjeta.” This was the word for pearl. It was also the name of Petra’s mother.

The flower’s sphere collapsed. The seeds whirled down to the spot on the floor where the rug had been. Astrophil squeaked as a panel slid away to reveal a hiding place he hadn’t known was there.

That had been too easy. Petra grinned and shook her head. She would have to tell her father to change the password when she returned.

Kneeling by the hole in the floor, she stuck her hand inside and gasped when it hit something hard. She touched cloth and dragged it into view. It was very heavy to pull. It was a sack tied with twine. She opened it quickly and saw—nothing. Bewildered, she thrust her hand inside and yelped when she hit that same hard something yet again. She shook away the pain and then felt inside the bag more gingerly, tracing the outline of something long and cylindrical, with a sharp, pointed end. Suddenly she realized what it was: a screwdriver. It was one of the invisible tools her father had made years ago. No wonder she could never find them in the shop! Her hand passed quickly over the tools, feeling several of them. What were they doing here?

She had no time to consider the answer. She roughly tied the bag again and shoved it back to where it had been. Then she continued to grope for anything that resembled papers or a notebook. When her fingertips touched a smooth vellum binding, she pulled it into sight. She did not pause to look inside the book but thrust it into her pack. As Astrophil tugged at her sleeve she fumbled for the hidden brass flower, pressed it, and was already dashing as quietly as she could out of the room when the panel in the floor slid shut.

TOMIK WAS WAITING for her by the road that led from Okno to Prague. “Where were you? It’s already dawn! Lucie and Pavel will be coming along any minute. Here.” He thrust a small cloth bag at her. “A little going-away present. Use them well. Actually, don’t use them unless you have to, since the effects will be … dramatic.”

Petra opened the bag and looked inside. Three glass balls winked up at her. “You didn’t,” she said.

“Oh, but I did. Sir Wasp is all yours.”

“What’s the third one?” She reached inside, fished around, and brought out a ball that did not contain an angry insect or a sliver of lightning. She lifted the sphere, and a small jet of water splashed inside.

“One Marvel, made to order. It was your idea to put water inside, remember?”

“Actually, it was Astro’s.” She shook the ball and stared at the water’s lovely dance.

“Indeed it was my idea.” Astrophil drew himself up to his full height.

“But she made some key suggestions,” Tomik told the spider. “Now, Petra, seriously: try to avoid breaking one unless you need to for protection from something. You know I haven’t tested the Hive.” He tapped the sphere with the wasp. “And I haven’t tried out the Bubble either. So don’t break them unless you have to.”

“What’s the one with lightning called?”

“Not sure. Any thoughts?”

Petra recalled what she had been thinking about before she fell asleep the night before: a lightning bug. “What about ‘Firefly’?”

Before Tomik could respond, they heard the clopping of horse hooves and the rattle of a carriage. He gave Petra a fierce hug. “See you in a couple of weeks!”

He broke away and began to walk swiftly into the trees. “Not sticking around for Lucie and Pavel?” she called.

He turned around. “I see enough of them as it is. By the way, take care to keep Astro hidden when you’re in the city. He could get stolen. And take care of yourself, too.”

SO FAR, SO GOOD. Lucie and Pavel didn’t look at the letter twice, and the young blond woman was thrilled to have Petra for company. Petra sat in the back of the cart, which chimed with glassware whenever the cart rattled against a bump in the road.

Lucie talked nonstop. She pointed out where poppies had grown along the road earlier that summer. “But they’re all gone now.” She sighed. “They were so red and pretty.”

Pavel looked lovingly at her. When a snake squiggled across the dirt road, the horse whickered and Lucie squealed. Pavel patted her arm. Petra rolled her eyes.

For most of the trip, Lucie hung her arm on the bench and twisted around to chat with Petra. The younger girl nodded along to whatever Lucie had to say, but she was impatient to look at the book she had taken from the secret panel in her father’s library. As the day grew darker, she stole a few glances at the pages. It was enough to confirm that the sketches were indeed of a large clock.

“May I read it?” Astrophil asked. Petra propped it open for the spider. His green eyes glowed in the twilight. He walked quickly across the page, scanning the scribbled notes. Soon he reached the bottom of the page, and then slipped beneath it. A bump appeared in the paper as Astrophil pushed it up from below. Then the page flipped over as if an unseen hand had turned it.