“That’s very nice of you,” Percy said. “But I’ve had enough poison for one trip. Now, can you hide us in your Death Mist, or not?”

“Yeah, it’ll be fun,” Annabeth said.

The goddess’s eyes narrowed. “Fun?”

“Sure,” Annabeth promised. “If we fail, think how great it will be for you, gloating over our spirits when we die in agony. You’ll get to say ‘I told you so’ for eternity.”

“Or, if we succeed,” Percy added, “think of all the suffering you’ll bring to the monsters down here. We intend to seal the Doors of Death. That’s going to cause a lot of wailing and moaning.”

Akhlys considered. “I enjoy suffering. Wailing is also good.”

“Then it’s settled,” Percy said. “Make us invisible.”

Akhlys struggled to her feet. The shield of Hercules rolled away and wobbled to a stop in a patch of poison flowers. “It is not so simple,” the goddess said. “The Death Mist comes at the moment you are closest to your end. Your eyes will be clouded only then. The world will fade.”

Percy’s mouth felt dry. “Okay. But…we’ll be shrouded from the monsters?”

“Oh, yes,” Akhlys said. “If you survive the process, you will be able to pass unnoticed among the armies of Tartarus. It is hopeless, of course, but if you are determined, then come. I will show you the way.”

“The way to where, exactly?” Annabeth asked.

The goddess was already shuffling into the gloom.

Percy turned to look at Bob, but the Titan was gone. How does a ten-foot-tall silver dude with a very loud kitten disappear?

“Hey!” Percy yelled to Akhlys. “Where’s our friend?”

“He cannot take this path,” the goddess called back. “He is not mortal. Come, little fools. Come experience the Death Mist.”

Annabeth exhaled and grabbed his hand. “Well…how bad can it be?”

The question was so ridiculous Percy laughed, even though it hurt his lungs. “Yeah. Next date, though—dinner in New Rome.”

They followed the goddess’s dusty footprints through the poison flowers, deeper into the fog.

PERCY MISSED BOB.

He’d gotten used to having the Titan on his side, lighting their way with his silver hair and his fearsome war broom.

Now their only guide was an emaciated corpse lady with serious self-esteem issues.

As they struggled across the dusty plain, the fog became so thick that Percy had to resist the urge to swat it away with his hands. The only reason he was able to follow Akhlys’s path was because poisonous plants sprang up wherever she walked.

If they were still on the body of Tartarus, Percy figured they must be on the bottom of his foot—a rough, calloused expanse where only the most disgusting plant life grew.

Finally they arrived at the end of the big toe. At least that’s what it looked like to Percy. The fog dissipated, and they found themselves on a peninsula that jutted out over a pitch-black void.

“Here we are.” Akhlys turned and leered at them. Blood from her cheeks dripped on her dress. Her sickly eyes looked moist and swollen but somehow excited. Can Misery look excited?

“Uh…great,” Percy asked. “Where is here?”

“The verge of final death,” Akhlys said. “Where Night meets the void below Tartarus.”

Annabeth inched forward and peered over the cliff. “I thought there was nothing below Tartarus.”

“Oh, certainly there is.…” Akhlys coughed. “Even Tartarus had to rise from somewhere. This is the edge of the earliest darkness, which was my mother. Below lies the realm of Chaos, my father. Here, you are closer to nothingness than any mortal has ever been. Can you not feel it?”

Percy knew what she meant. The void seemed to be pulling at him, leaching the breath from his lungs and the oxygen from his blood. He looked at Annabeth and saw that her lips were tinged blue.

“We can’t stay here,” he said.

“No, indeed!” Akhlys said. “Don’t you feel the Death Mist? Even now, you pass between. Look!”

White smoke gathered around Percy’s feet. As it coiled up his legs, he realized the smoke wasn’t surrounding him. It was coming from him. His whole body was dissolving. He held up his hands and found they were fuzzy and indistinct. He couldn’t even tell how many fingers he had. Hopefully still ten.

He turned to Annabeth and stifled a yelp. “You’re—uh—”

He couldn’t say it. She looked dead.

Her skin was sallow, her eye sockets dark and sunken. Her beautiful hair had dried into a skein of cobwebs. She looked like she’d been stuck in a cool, dark mausoleum for decades, slowly withering into a desiccated husk. When she turned to look at him, her features momentarily blurred into mist.

Percy’s blood moved like sap in his veins.

For years, he had worried about Annabeth dying. When you were a demigod, that went with the territory. Most half-bloods didn’t live long. You always knew that the next monster you fought could be your last. But seeing Annabeth like this was too painful. He’d rather stand in the River Phlegethon, or get attacked by arai, or be trampled by giants.

“Oh, gods,” Annabeth sobbed. “Percy, the way you look…”

Percy studied his arms. All he saw were blobs of white mist, but he guessed that to Annabeth he looked like a corpse. He took a few steps, though it was difficult. His body felt insubstantial, like he was made of helium and cotton candy.

“I’ve looked better,” he decided. “I can’t move very well. But I’m all right.”

Akhlys clucked. “Oh, you’re definitely not all right.”

Percy frowned. “But we’ll pass unseen now? We can get to the Doors of Death?”

“Well, perhaps you could,” the goddess said, “if you lived that long, which you won’t.”

Akhlys spread her gnarled fingers. More plants bloomed along the edge of the pit—hemlock, nightshade, and oleander spreading toward Percy’s feet like a deadly carpet. “The Death Mist is not simply a disguise, you see. It is a state of being. I could not bring you this gift unless death followed—true death.”

“It’s a trap,” Annabeth said.

The goddess cackled. “Didn’t you expect me to betray you?”

“Yes,” Annabeth and Percy said together.

“Well, then, it was hardly a trap! More of an inevitability. Misery is inevitable. Pain is—”

“Yeah, yeah,” Percy growled. “Let’s get to the fighting.”

He drew Riptide, but the blade was made of smoke. When he slashed at Akhlys, the sword just floated across her like a gentle breeze.

The goddess’s ruined mouth split into a grin. “Did I forget to mention? You are only mist now—a shadow before death. Perhaps if you had time, you could learn to control your new form. But you do not have time. Since you cannot touch me, I fear any fight with Misery will be quite one-sided.”

Her fingernails grew into talons. Her jaw unhinged, and her yellow teeth elongated into fangs.

AKHLYS LUNGED AT PERCY, and for a split second he thought: Well, hey, I’m just smoke. She can’t touch me, right?

He imagined the Fates up in Olympus, laughing at his wishful thinking: LOL, NOOB!

The goddess’s claws raked across his chest and stung like boiling water.

Percy stumbled backward, but he wasn’t used to being smoky. His legs moved too slowly. His arms felt like tissue paper. In desperation, he threw his backpack at her, thinking maybe it would turn solid when it left his hand, but no such luck. It fell with a soft thud.

Akhlys snarled, crouching to spring. She would have bitten Percy’s face off if Annabeth hadn’t charged and screamed, “HEY!” right in the goddess’s ear.

Akhlys flinched, turning toward the sound.

She lashed out at Annabeth, but Annabeth was better at moving than Percy. Maybe she wasn’t feeling as smoky, or maybe she’d just had more combat training. She’d been at Camp Half-Blood since she was seven. Probably she’d had classes Percy never got, like How to Fight While Partially Made of Smoke.

Annabeth dove straight between the goddess’s legs and somersaulted to her feet. Akhlys turned and attacked, but Annabeth dodged again, like a matador.

Percy was so stunned, he lost a few precious seconds. He stared at corpse Annabeth, shrouded in mist but moving as fast and confidently as ever. Then it occurred to him why she was doing this: to buy them time. Which meant Percy needed to help.

He thought furiously, trying to come up with a way to defeat Misery. How could he fight when he couldn’t touch anything?

On Akhlys’s third attack, Annabeth wasn’t so lucky. She tried to veer aside, but the goddess grabbed Annabeth’s wrist and pulled her hard, sending her sprawling.

Before the goddess could pounce, Percy advanced, yelling and waving his sword. He still felt about as solid as a Kleenex, but his anger seemed to help him move faster.

“Hey, Happy!” he yelled.

Akhlys spun, dropping Annabeth’s arm. “Happy?” she demanded.

“Yeah!” He ducked as she swiped at his head. “You’re downright cheerful!”

“Arggh!” She lunged again, but she was off balance. Percy sidestepped and backed away, leading the goddess farther from Annabeth.

“Pleasant!” he called. “Delightful!”

The goddess snarled and winced. She stumbled after Percy. Each compliment seemed to hit her like sand in the face.

“I will kill you slowly!” she growled, her eyes and nose watering, blood dripping from her cheeks. “I will cut you into pieces as a sacrifice to Night!”

Annabeth struggled to her feet. She started rifling through her pack, no doubt looking for something that might help.

Percy wanted to give her more time. She was the brains. Better for him to get attacked while she came up with a brilliant plan.

“Cuddly!” Percy yelled. “Fuzzy, warm, and huggable!”

Akhlys made a growling, choking noise, like a cat having a seizure.

“A slow death!” she screamed. “A death from a thousand poisons!”

All around her, poisonous plants grew and burst like overfilled balloons. Green-and-white sap trickled out, collecting into pools, and began flowing across the ground toward Percy. The sweet-smelling fumes made his head feel wobbly.

“Percy!” Annabeth’s voice sounded far away. “Uh, hey, Miss Wonderful! Cheerful! Grins! Over here!”

But the goddess of misery was now fixated on Percy. He tried to retreat again. Unfortunately the poison ichor was flowing all around him now, making the ground steam and the air burn. Percy found himself stuck on an island of dust not much bigger than a shield. A few yards away, his backpack smoked and dissolved into a puddle of goo. Percy had nowhere to go.

He fell to one knee. He wanted to tell Annabeth to run, but he couldn’t speak. His throat was as dry as dead leaves.

He wished there were water in Tartarus—some nice pool he could jump into to heal himself, or maybe a river he could control. He’d settle for a bottle of Evian.