“Yeah,” Percy agreed. “Maybe the maple tree died, and he wound up back here?”

Annabeth remembered how Hyperion had summoned fiery explosions, and how many satyrs and nymphs he’d destroyed before Percy and Grover stopped him.

She was about to suggest that they burst Hyperion’s bubble before he woke up. He looked ready to pop out at any moment and start charbroiling everything in his path.

Then she glanced at Bob. The silvery Titan was studying Hyperion with a frown of concentration—maybe recognition. Their faces looked so much alike.…

Annabeth bit back a curse. Of course they looked alike. Hyperion was his brother. Hyperion was the Titan lord of the east. Iapetus, Bob, was the lord of the west. Take away Bob’s broom and his janitor’s clothes, put him in armor and cut his hair, change his color scheme from silver to gold, and Iapetus would have been almost indistinguishable from Hyperion.

“Bob,” she said, “we should go.”

“Gold, not silver,” Bob murmured. “But he looks like me.”

“Bob,” Percy said. “Hey, buddy, over here.”

The Titan reluctantly turned.

“Am I your friend?” Percy asked.

“Yes.” Bob sounded dangerously uncertain. “We are friends.”

“You know that some monsters are good,” Percy said. “And some are bad.”

“Hmm,” Bob said. “Like…the pretty ghost ladies who serve Persephone are good. Exploding zombies are bad.”

“Right,” Percy said. “And some mortals are good, and some are bad. Well, the same thing is true for Titans.”

“Titans…” Bob loomed over them, glowering. Annabeth was pretty sure her boyfriend had just made a big mistake.

“That’s what you are,” Percy said calmly. “Bob the Titan. You’re good. You’re awesome, in fact. But some Titans are not. This guy here, Hyperion, is full-on bad. He tried to kill me…tried to kill a lot of people.”

Bob blinked his silver eyes. “But he looks…his face is so—”

“He looks like you,” Percy agreed. “He’s a Titan, like you. But he’s not good like you are.”

“Bob is good.” His fingers tightened on his broom handle. “Yes. There is always at least one good one—monsters, Titans, giants.”

“Uh…” Percy grimaced. “Well, I’m not sure about the giants.”

“Oh, yes.” Bob nodded earnestly.

Annabeth sensed they’d already been in this place too long. Their pursuers would be closing in.

“We should go,” she urged. “What do we do about…?”

“Bob,” Percy said, “it’s your call. Hyperion is your kind. We could leave him alone, but if he wakes up—”

Bob’s broom-spear swept into motion. If he’d been aiming at Annabeth or Percy, they would’ve been cut in half. Instead, Bob slashed through the monstrous blister, which burst in a geyser of hot golden mud.

Annabeth wiped the Titan sludge out of her eyes. Where Hyperion had been, there was nothing but a smoking crater.

“Hyperion is a bad Titan,” Bob announced, his expression grim. “Now he can’t hurt my friends. He will have to re-form somewhere else in Tartarus. Hopefully it will take a long time.”

The Titan’s eyes seemed brighter than usual, as if he were about to cry quicksilver.

“Thank you, Bob,” Percy said.

How was he keeping his cool? The way he talked to Bob left Annabeth awestruck…and maybe a little uneasy, too. If Percy had been serious about leaving the choice to Bob, then she didn’t like how much he trusted the Titan. If he’d been manipulating Bob into making that choice…well, then, Annabeth was stunned that Percy could be so calculating.

He met her eyes, but she couldn’t read his expression. That bothered her too.

“We’d better keep going,” he said.

She and Percy followed Bob, the golden mud flecks from Hyperion’s burst bubble glowing on his janitor’s uniform.

AFTER A WHILE, Annabeth’s feet felt like Titan mush. She marched along, following Bob, listening to the monotonous slosh of liquid in his cleaning bottle.

Stay alert, she told herself, but it was hard. Her thoughts were as numb as her legs. From time to time, Percy took her hand or made an encouraging comment; but she could tell the dark landscape was getting to him as well. His eyes had a dull sheen—like his spirit was being slowly extinguished.

He fell into Tartarus to be with you, said a voice in her head. If he dies, it will be your fault.

“Stop it,” she said aloud.

Percy frowned. “What?”

“No, not you.” She tried for a reassuring smile, but she couldn’t quite muster one. “Talking to myself. This place…it’s messing with my mind. Giving me dark thoughts.”

The worry lines deepened around Percy’s sea-green eyes. “Hey, Bob, where exactly are we heading?”

“The lady,” Bob said. “Death Mist.”

Annabeth fought down her irritation. “But what does that mean? Who is this lady?”

“Naming her?” Bob glanced back. “Not a good idea.”

Annabeth sighed. The Titan was right. Names had power, and speaking them here in Tartarus was probably very dangerous.

“Can you at least tell us how far?” she asked.

“I do not know,” Bob admitted. “I can only feel it. We wait for the darkness to get darker. Then we go sideways.”

“Sideways,” Annabeth muttered. “Naturally.”

She was tempted to ask for a rest, but she didn’t want to stop. Not here in this cold, dark place. The black fog seeped into her body, turning her bones into moist Styrofoam.

She wondered if her message would get to Rachel Dare. If Rachel could somehow carry her proposal to Reyna without getting killed in the process…

A ridiculous hope, said the voice in her head. You have only put Rachel in danger. Even if she finds the Romans, why should Reyna trust you after all that has happened?

Annabeth was tempted to shout back at the voice, but she resisted. Even if she were going crazy, she didn’t want to look like she was going crazy.

She desperately needed something to lift her spirits. A drink of actual water. A moment of sunlight. A warm bed. A kind word from her mother.

Suddenly Bob stopped. He raised his hand: Wait.

“What?” Percy whispered.

“Shh,” Bob warned. “Ahead. Something moves.”

Annabeth strained her ears. From somewhere in the fog came a deep thrumming noise, like the idling engine of a large construction vehicle. She could feel the vibrations through her shoes.

“We will surround it,” Bob whispered. “Each of you, take a flank.”

For the millionth time, Annabeth wished she had her dagger. She picked up a chunk of jagged black obsidian and crept to the left. Percy went right, his sword ready.

Bob took the middle, his spearhead glowing in the fog.

The humming got louder, shaking the gravel at Annabeth’s feet. The noise seemed to be coming from immediately in front of them.

“Ready?” Bob murmured.

Annabeth crouched, preparing to spring. “On three?”

“One,” Percy whispered. “Two—”

A figure appeared in the fog. Bob raised his spear.

“Wait!” Annabeth shrieked.

Bob froze just in time, the point of his spear hovering an inch above the head of a tiny calico kitten.

“Rrow?” said the kitten, clearly unimpressed by their attack plan. It butted its head against Bob’s foot and purred loudly.

It seemed impossible, but the deep rumbling sound was coming from the kitten. As it purred, the ground vibrated and pebbles danced. The kitten fixed its yellow, lamp-like eyes on one particular rock, right between Annabeth’s feet, and pounced.

The cat could’ve been a demon or a horrible Underworld monster in disguise. But Annabeth couldn’t help it. She picked it up and cuddled it. The little thing was bony under its fur, but otherwise it seemed perfectly normal.

“How did…?” She couldn’t even form the question. “What is a kitten doing…?”

The cat grew impatient and squirmed out of her arms. It landed with a thump, padded over to Bob, and started purring again as it rubbed against his boots.

Percy laughed. “Somebody likes you, Bob.”

“It must be a good monster.” Bob looked up nervously. “Isn’t it?”

Annabeth felt a lump in her throat. Seeing the huge Titan and this tiny kitten together, she suddenly felt insignificant compared to the vastness of Tartarus. This place had no respect for anything—good or bad, small or large, wise or unwise. Tartarus swallowed Titans and demigods and kittens indiscriminately.

Bob knelt down and scooped up the cat. It fit perfectly in Bob’s palm, but it decided to explore. It climbed the Titan’s arm, made itself at home on his shoulder, and closed its eyes, purring like an earthmover. Suddenly its fur shimmered. In a flash, the kitten became a ghostly skeleton, as if it had stepped behind an X-ray machine. Then it was a regular kitten again.

Annabeth blinked. “Did you see—?”

“Yeah.” Percy knit his eyebrows. “Oh, man…I know that kitten. It’s one of the ones from the Smithsonian.”

Annabeth tried to make sense of that. She’d never been to the Smithsonian with Percy.… Then she recalled several years ago, when the Titan Atlas had captured her. Percy and Thalia had led a quest to rescue her. Along the way, they’d watched Atlas raise some skeleton warriors from dragon teeth in the Smithsonian Museum.

According to Percy, the Titan’s first attempt went wrong. He’d planted saber-toothed tiger teeth by mistake, and raised a batch of skeleton kittens from the soil.

“That’s one of them?” Annabeth asked. “How did it get here?”

Percy spread his hands helplessly. “Atlas told his servants to take the kittens away. Maybe they destroyed the cats and they were reborn in Tartarus? I don’t know.”

“It’s cute,” Bob said, as the kitten sniffed his ear.

“But is it safe?” Annabeth asked.

The Titan scratched the kitten’s chin. Annabeth didn’t know if it was a good idea, carrying around a cat grown from a prehistoric tooth; but obviously it didn’t matter now. The Titan and the cat had bonded.

“I will call him Small Bob,” said Bob. “He is a good monster.”

End of discussion. The Titan hefted his spear and they continued marching into the gloom.

Annabeth walked in a daze, trying not to think about pizza. To keep herself distracted, she watched Small Bob the kitten pacing across Bob’s shoulders and purring, occasionally turning into a glowing kitty skeleton and then back to a calico fuzz-ball.

“Here,” Bob announced.

He stopped so suddenly, Annabeth almost ran into him.

Bob stared off to their left, as if deep in thought.

“Is this the place?” Annabeth asked. “Where we go sideways?”

“Yes,” Bob agreed. “Darker, then sideways.”