With their headlamps switched off, the friends lay on the ground, hearts pounding. The monstrous presence above them suddenly shifted, and more dust fell upon their shoulders.

Somes couldn’t stay still any longer—he snapped on his headlamp and looked up. A milky glass ceiling reflected the light’s beam. Transparent riblike shapes caught the light, and floating objects passed by, suspended in what appeared to be a clear jelly.

Suddenly, the whole ceiling shifted, and Somes realized what it was.

When he told Abby, she went rigid. “Oh, gosh, gosh, gosh,” she muttered.

“What?” said Pamela.

“It’s a megamorphic see-through thing,” said Somes.

“A what? And how can it be see-through?” asked Gabriel.

“I forget what they’re called,” said Somes.

“Haven’t you seen those pictures of living things in the deepest trenches of the ocean?” whispered Abby. “They don’t need color because nothing can see them, so they’re transparent. No pigment at all.”

“Will it eat us?” asked Pamela.

“I don’t know, but I can see what it’s eaten.” Somes’s hand trembled as he pointed the beam at things floating in the clear ooze: a milk crate, a soda bottle, boots, and a winged skeleton.

“If we just stay still, we’ll be safe. Right, Abby?” asked Somes.

“Unless it’s a snake,” Abby replied.

“Why?” asked Gabriel.

“Most predators can’t see you if you keep still. But snakes have thermal vision; if you’re warm, you glow like a red light. Our only chance is to be cold and dead.”

“I think it’s a snake,” said Somes miserably. “It looks like a snake.”

“I have a snake,” Abby announced. “His name’s Mr. Squirmington. And he only eats live food. But you can spook him pretty easily.”

“So how do we spook a snake that’s a zillion times bigger than we are?” wondered Gabriel.

Somes looked at Pamela. “Did you bring your violin?”

“Not this time,” she replied.

“Snakes can’t really hear the way we do,” Abby reminded him. “All that stuff about snake charmers hypnotizing cobras with music is horse poop. We need another way to scare it.”

“I don’t want to be bitten,” said Somes. “Not by teeth as big as ninja swords.”

“Don’t worry,” said Abby. “We’ll probably be swallowed whole, then dissolved by acids in its stomach. It’ll take months.”

Suddenly, Gabriel noticed a pain in his belly; he wasn’t sure if it was fear or simply hunger, but it seemed a bitter fate to be digested while feeling hungry, too. “Hey, Abby,” he said. “What do you have to eat in your backpack?”

“Snack bars left over from last summer,” she said.

Gabriel rummaged through the backpack. “What’s in these boxes?”

“Boxes?…Oh, sparklers from the Fourth of July. Last year it rained all week, so I never used them.”

“Do you have matches?” said Somes.

“Of course,” said Abby.

“A box of flaming sparklers might freak out a snake,” said Gabriel.

Abby passed the sparklers around and then lit them. As sparks began to fly, the serpent quivered and shifted with obvious distress.

“Wave them around!” said Gabriel.

Exaggerating their gestures, the children made brilliant shapes in the darkness.

The creature’s reaction was swift. Startled and confused, it drew its body into tight coils, its glassy ribs contracted, and its thin, transparent scales quivered. Prominent fangs were visible behind a weaving tongue, glossy and clear as glass.

Abby was quick to point out that snakes can swallow something three times the size of their own heads. “Even if you hid inside a small car, this thing could swallow it.”

“Oh, great. Thanks,” muttered Somes. He lit more sparklers and tossed them at the snake’s eyes.

This startled the serpent more than anything else. It reared up and hissed.

“Everybody!” cried Somes to the others. “Copy me!”

The others threw their sparklers at the snake’s head. One of Pamela’s struck it in the eye. It immediately jerked away from them.

“Good one, Pamela!” cried Gabriel.

As the serpent retreated in frantic movements, its enormous limpid body rustled across the rocky surface, coils winding a graceful and swift escape into the darker recesses of the cave.

“We did it!” shouted Abby. “Now let’s just hope we don’t bump into it around another corner.”

Giddy at having defeated the serpent, the foursome hurried along the tunnel. Occasionally, they caught a glimpse of a vast abandoned city above them. Their headlamps moved too quickly to illuminate much, but Gabriel saw fallen pillars and fragments of pediments and archways. He counted hundreds of windows—all dark and vacant: the remnants of Aviopolis.

Everyone began to complain of being hungry, so they finished off the snack bars from Abby’s backpack.

Presently, they came to a fork in the tunnel. The little group hesitated.

“Let’s split up,” suggested Gabriel at last. “If one of us gets somewhere, we’ll call out.”

“Okay,” said Somes. “C’mon, Pamela,” and he took the right turn.

Gabriel and Abby headed left.

“Wait, Somes!” cried Abby, moments later. “We’re at another fork.”

“We found a fork, too,” called Pamela. “Let’s meet up and figure this out.”

“Tunnels going in every direction with no signs,” said Abby when they’d joined up again. “This must be a maze.”

“No, no, it must lead somewhere,” said Pamela.

“Look what I found,” said Somes. He held up a dirty, round object. As their headlamp beams converged, they recognized the eye cavities and teeth of a human skull.

“Ugh.” Somes dropped the skull and wiped his hands on his pants. “I hate this place.”

Abby rubbed her glasses. “Why would anyone build a maze here, anyway?”

“To make the Chamber of Runes hard to find?” suggested Gabriel.

“Or,” said Pamela, “so we could die of thirst or hunger before we find it.”

A grim sense of despair settled over the group.

“Wait a minute,” said Gabriel. “Does anybody remember Mr. Coffin’s riddle? He put a maze on the board and said even a blind person could find the way out.”

“That was a just game,” Somes said. “This is real.”

“Yeah, but the rules are the same,” said Abby. “Follow the wall and it will lead you out. It’s the rule.”

“Unless there are a bunch of exits. Then we’ll still be lost,” said Somes.

“Okay, guys, we can give up and go home,” said Pamela. “Or we can give it a try. What do you think, Gabriel?”

Gabriel looked at their faces. He didn’t want any of his friends to come to harm. On the other hand, he felt so close to finding his mother and was convinced that his father would need his help in some way. “Let’s do it,” he said.

“Remember, Septimus got through the maze,” said Abby with a hopeful smile. “And he’s a chickenhearted scaredy pants.”

“Follow the wall,” said Gabriel, looking at the others. “Okay?”

Everybody nodded. Gabriel took the first left fork, touching the tunnel wall lightly with his left hand. The corridor split, then split again, as onward they walked. There were many dead ends, but they always stuck to the wall on the left, no matter how it turned and twisted. They moved quickly as they became comfortable with the plan, and the speed of their pace made them more confident.

“Gabriel?” whispered Abby after a while. “Don’t you think it’s weird that Mr. Coffin has helped us twice on this trip?”

“And I’m still wondering about that raven tattoo on his wrist,” said Gabriel. “And the thing he said about fighting your demons. I wonder if he was talking about Corax.”

“Hey, don’t be so sure he’s a good dude,” muttered Somes from behind. “He gave me two Ds and marked me down for missing Friday’s homework.”

—

A half hour later, the twisting corridor of rock opened upon a plateau with a gloomy view of ruins extending across the floor of a vast cavern. Just ahead, a gleaming passageway of smooth, shiny blue stone seemed to beckon to the children. As they ventured forward, the air became warmer and the corridor reflected light from some distant source. The foursome shed their jackets and headlamps in a heap and continued toward the beckoning glow.

Abby paused and squinted at the passage wall. “It’s lapis lazuli,” she said. “A kind of gemstone.”

“How do you know that?” said Somes.

“My sister Etta makes earrings out of it.”

“Of course she does,” said Somes, rolling his eyes.

“There’s nothing wrong with knowing things,” Abby added.

Pamela gave Somes a warning glance. When he said nothing, she pinched him.

“Ow!” he cried. “Why’d you do that?”

“That wasn’t nice,” she said.

Gabriel stopped and turned around. “Guys? Chill, okay?”

The polished blue corridor curved around to a point where they couldn’t see its beginning or end, but then they heard a familiar voice. “The remarkable thing about the language of Gutnish is that there are twenty-six words for darkness.”

It was Adam Finley. He spoke in a pedantic tone, as if lecturing to a hall of students.

Septimus’s voice replied, “You don’t say.”

“There’s goyt, which means the darkness of a gold mine,” Adam continued. “Doyt, the darkness of a tomb; hoyt, the hopeful darkness before the dawn; poyt, the pitiful darkness of being alone; and boyt, the wholesome darkness of strong Gutnish beer. There’s also—”

“Goyt, doyt, hoyt, poyt, boyt!” interrupted Septimus. “Get to the point!”

The children tiptoed toward the voices and came to two open brass doors. Beyond the doorway, Mr. Finley and Septimus Geiger could be seen in a domed room. The ceiling curved down to the floor, and in the room’s center stood a round pedestal rimmed by lapping blue flames. Several stones rested within the circle of fire.

Adam and Septimus peered at the stones. Each one appeared to be translucent, with a silhouette in its center.

“Those must be the real runes,” whispered Gabriel.

Septimus turned around. “What are you doing here?” he snapped. “Finley, you promised you were coming alone.”

“I did come alone,” replied Adam.

“Sorry, Dad,” said Gabriel. “I had to.”

“We almost got eaten by a big glass serpent,” interrupted Abby cheerfully.

“Serpent? Oh, you mean the subterranean rock boa,” said Septimus.

“It’s okay, we scared it away,” said Pamela.

“With sparklers,” added Somes.

“Oh, I wish you hadn’t,” said Septimus.

“Why not?”

Septimus scowled. “She keeps the valravens away.”

“We haven’t seen any valravens,” said Gabriel.

“The subterranean rock boa eats them,” explained Septimus. “Of course, if she disappears for a few days because of your stupidity, the valravens will be back, screaming for fresh meat.”

“She could have eaten us,” said Gabriel.

“Nonsense! She’s as pleasant as a pussycat.” Septimus sniffed. “Whales are huge, but they don’t eat people, do they? It’s such arrogance to think you’re worthy of being eaten.”

Gabriel looked over at his father, expecting him to be upset. But his father seemed pleased that he had arrived.

“Look here, Gabriel,” he said. Mr. Finley pointed to one of the three runes. Inside, Gabriel saw a small silhouette of a woman. Just a shadow, but her head turned, suddenly, as if she’d noticed him. Gabriel felt a sudden ache in his chest.

“It’s her,” said Adam. “Your mother.”

Gabriel reached toward the stone, but Septimus grabbed his hand and jerked it away.

“Let’s be clear on one thing,” he said sharply. “Your father promised he’d free Corax first. That was his oath, sworn on a Flaming Truth Toddy.”

“Really, Dad?” said Gabriel with disbelief.

Mr. Finley looked apologetic. “It was the only way, Gabriel.”

“Can’t you change your mind?”

“No, he can’t!” Septimus barked. “If you break a promise made with a toddy, your pants will burn like a bonfire.” Septimus put a tender hand to his scorched trousers. “Take my word for it.”

Mr. Finley tried to reassure Gabriel. “Everything will be fine. I must do exactly what I promised. I must try to free Corax,” he whispered softly. “But at least now you know where your mother is….”

As his father’s voice trailed off, Gabriel realized that Mr. Finley had been counting on Gabriel to follow him all along. And this made him wonder why his father had agreed to such a terrible bargain.