Nico had no idea where he was relative to the staging area he’d‌

stumbled on before, but he figured Nemesis must have dropped him someplace far, far away.

Because this part of Tartarus was empty.

The land seemed to stretch on forever. Nico was thankful that Nemesis had given him some guidance, because if he hadn’t kept himself to the left of the River Phlegethon, he would’ve had no idea where to go. After hours of walking on the strange marshy ground, Nico was exhausted. Hungry. His feet ached, and his lungs burned from the sooty air.

Something else was happening to him, too.

The world around him … It seemed to be shifting. That was the only way he could describe it. He’d be staring into the distance, where mist clung to a dark expanse of forest, and for the briefest of moments the horizon would leap backwards like a mirage. The landscape before him took on sharper

edges, with colours so terrifyingly intense that they hurt his eyes. The land itself seemed to be rising and falling, as if it were breathing. Or was Nico imagining that?

He had no one to compare notes with, so he kept walking. The river flowed smoothly past him, and if it hadn’t been made of pure fire, he

would’ve wished for a boat – anything that could keep him moving towards the bottom of Tartarus and closer to his goal.

Sometimes he heard cries in the distance: definitely not human, full of rage and defiance. Perhaps they were creatures awakening in the darkness, crawling from their regeneration pits, ready to head back to the world

above, or to join Gaia’s army. He remembered what Nemesis had said: All of them desire nothing but retribution.

He forced himself to keep walking. The fate of the whole world depended on him finding and closing the Doors of Death.

As the forest grew closer, the temperature dropped. Nico zipped up his leather jacket and kept his hands in his pockets, but soon he was shivering. This shouldn’t have been possible with a flaming river literally right next to him, but somehow the closeness of the Phlegethon didn’t cut through the

cold. If anything, it made things worse. A part of Nico’s mind begged him to jump in, to experience the warmth it would provide for a few seconds before he burned up.

‘Stop that,’ he told himself out loud. ‘Don’t let this place break you down.’

But it was, wasn’t it? The deeper Nico went into Tartarus, the more it sanded off the edges of his sanity. He was now convinced he was full-on

hallucinating. The ground beneath him was definitely breathing, albeit very slowly, and those dark regenerating blisters were now spread so thickly in his path that he had to squeeze between them in order to keep moving. He felt like a mite crawling across a giant’s stubbly face. Once, he heard the

sickening pop as a blister burst open somewhere nearby. He stopped, his sword glowing gently at his side, but whatever monster had emerged he heard it scampering away, heading upriver.

Nico’s throat was so dry that his tongue was stuck to the roof of his mouth. He had to reach in with a finger to prise it off, which only caused him to break out in a deep cough.

And meanwhile the River Phlegethon just kept rolling along.

It moved like water. To Nico’s delirious mind, it had even started to look like water. But … it was fire. Right?

Nico searched his memories for information about the Phlegethon. For the first time in years, he thought about his old Mythomagic cards. Was there any lore in that game about what would happen if a mortal drank from the River of Fire?

He couldn’t remember. He couldn’t believe he was even considering it.

Then Tartarus shuddered. The ground shifted sideways, throwing Nico off his feet.

He tumbled to the bank of the Phlegethon, his hands digging into the fine sand. Ash and cinders swirled around him, making him cough up sour

mucus. Huh. The Phlegm-a-thon, he thought. Bet I’m the first person to think of that.

Up close, the sound of the river was less like roaring fire and more like gentle babbling. It seemed to call out to him, as if begging him to drink.

No. No, he couldn’t. He hauled himself upright. When he turned again towards the dark forest, it was much closer, no more than a stone’s throw

away. And in the green fog, between the twisted dark branches of the trees, thousands upon thousands of tiny, glowing eyes stared back at him.

He couldn’t have cried out if he wanted to. His throat was too parched. He blinked away the soot and, when he looked up again, the forest’s eyes had vanished. The ground beneath him, though, was still heaving restlessly. Like it was alive.

He froze.

Oh.

Oh, Hades.

He tried to gulp down his fear. He knelt and put his hand on the ground, his fingers sinking into the fine sand. Underneath was a layer of … not soil, exactly. Not marsh. More like hide. It all came to him suddenly – Tartarus was not just a place. Tartarus was a living being – the sleeping body of a primordial god, and here Nico sat, right on top of its skin.

He sobbed, overwhelmed by how far he was from home. The thought made him cry harder because he wasn’t even sure where home was. Camp Half-Blood? Camp Jupiter? At this point, he would take either one, because they were both better than this.

High above him, a dark shape soared through the poison clouds, heading north. Its wingspan had to be ten or fifteen metres. More creatures followed it, like colossal geese in formation, and Nico assumed they were going to join up with Gaia’s forces.

What had Nico been thinking? Why had he come down here alone? No one even knew that he’d ventured into Tartarus, and even if someone did, they couldn’t help him. Tartarus wasn’t the kind of place you just strolled into.

He was going to die down here, wasn’t he? What happened to a demigod who died in Tartarus? Could they even reach the afterlife, or would they be trapped here forever, maybe drowning in one of those covered goo pits, unable to break free?

The ground rose again, shuddering, as if the entire landscape was tossing and turning in its sleep. Nico was so thirsty … He stared at the burning

water. He wanted to drink so badly …

For some reason, his mind went back to Dante’s Divine Comedy, which his mom had read to him when he was younger. Being Italian, she’d insisted that Nico learn at least some Dante by heart. She’d read those poems to him at bedtime – stories about descending into the Inferno and clawing your

way up again into the light of Purgatory. Almost like she’d been preparing him to know the truth about his father, or preparing him for this journey … Somewhere in those cantos, there’d been a moment when Dante faced a

wall of fire. His guide Virgil had convinced him to walk through it, despite his fears: Qui può esser tormento, ma non morte. Here you can be tormented, but not die.

It was wishful thinking that the Phlegethon would work like that. Then

again, Tartarus would eventually kill him anyway, wouldn’t it? Monsters he could fight. But thirst … that would be slower, more painful and just as lethal.

Nico knelt. Hesitantly, he touched the surface of the ‘water’.

It was freezing. He yanked his fingers back, only to discover that his skin was still very much intact and very much not on fire. He waited a few

seconds, certain that his pain receptors would kick in, or that he would combust.

But no. His hand ached from the cold, but there were no burn marks. He removed his jacket and set it aside.

Here goes nothing, he thought. Then his thirst took over.

He cupped his hands, dipped them in the icy flames and brought the water to his lips.

The effect was instantaneous. He choked and gagged, the fire raging down his throat and into his belly. He clutched at his stomach. His vision doubled, and he was certain this was the end. This was how he’d go out: curled up next to the River of Fire. From which he’d DRUNK like a fool.

But the pain began to fade. Nico lay there, gasping, and his exhaustion began to slip away. The soles of his feet no longer ached. His head felt

clearer.

Nico sat up, and the burning … was all gone. Not only that, he no longer felt thirsty.

Had just a small sip of the Phlegethon done all that?

He decided not to question it any further. It was a win-win. He wasn’t dead, and he’d just figured out that he could survive if he drank from a literal river of fire. Nico grabbed his leather jacket and slipped it on, then stood up and brushed himself off.

The forest awaited him. As did the Doors of Death. So the son of Hades kept going.

Days passed.

Or maybe it was hours. Or weeks. Or months, for that matter. Nemesis had warned him about her mother, who only came out during the day, but Nico had no sense of when one day might be passing into another down here. The light did not change. The weather was always hellish with an 80 percent chance of noxious clouds and scattered monsters. Tartarus simply pressed down on his spirit as Nico moved deeper and deeper, following the Phlegethon as it cut through the forest.

He went as long as he could between sips from the river. He had no idea if there were any long-term effects from drinking fire, but the river water

seemed to heal any exhaustion or pain that Nico was experiencing. It did not help him with the mental ramifications of being in Tartarus. He missed the sun. And solid food. He missed Camp Half-Blood and the satyrs and Chiron’s stern fatherly voice, and even the way Mr D whined and

complained as if he were being murdered continuously day in and day out. Nico missed the other demigods, like Percy and Annabeth and Jason, even if he wasn’t sure they missed him.

It didn’t help that the forest – thick with a smelly, sulphurous fog – was so thoroughly unlike any woods Nico had ever been in. The trees contorted around one another, and the branches seemed to bend ever so slowly in

Nico’s direction, even though the trunks looked completely dead, rotten on the inside and falling apart. Nico could not see above the treetops because of the impossible fog, but he heard creatures flying above, whooping and

shrieking. Bushes like tumbleweeds – but with much sharper thorns and burrs – clogged the forest floor, and Nico often had to use his sword to clear his way, which sent small lizard-rat creatures scurrying away from him.

The glowing eyes were back, too: always floating in the shadows at the edge of his vision, always watching him. He wondered why the owners of those eyes never approached or attacked. What were they waiting for?

There were far more of them than there was of him. Nico stayed on constant guard, awaiting the inevitable, and the anticipation was perhaps worse than if he’d actually been attacked.

He was so focused on the eyes that he barely realized that he’d reached the far side of the forest. The fog suddenly lifted, and he was met with an unending and impenetrable wall of darkness. It stretched in every direction, as far as he could see. Even the River Phlegethon made a sharp left turn and wended off to the north, as if it didn’t want to deal with that darkness. Nico stopped and stared, uncertain of what to do. How could Tartarus just end like that?

The ground below him continued for a few metres, so he took a step.

Then another.

Then a narrow rift appeared in the darkness: a vertical fissure that revealed a dirt pathway sloping down gently until it ended at a black stone

archway, not unlike the masonry on the parapets of Erebos. It looked like … A doorway.

Was it the doorway?

The idea was appealing. What if the Doors of Death weren’t some huge gates guarded by countless monsters from Gaia’s army but just a simple

arch hidden in the middle of nowhere?

Nico didn’t want to get too excited, yet it was hard to contain himself. He moved forward onto the dirt path. He tested it with a single footstep. It did not give way. The walls of darkness on either side did not close in on him.

Okay, he thought. Feels real enough.

Another step. Another. He was halfway across when he felt compelled to look behind himself for a second. The Phlegethon cast an eerie glow over the trees. Nico was afraid to leave the only source of water that had been keeping him alive, but … he had to. He felt sure this was where he was

supposed to be.

Near the end of the path, he noticed something about the archway that he couldn’t have seen from a distance.

The black stone was moving.

Not shifting as a whole, but the arch appeared to be made of millions of tiny … well, he didn’t know what he was looking at. Particles of dust?

Quicksand? He reached out to touch it, then jerked his hand away.

No, he thought. Don’t do that. Something is wrong.

Maybe he wasn’t at the Doors of Death after all. He turned again, looking wistfully back up the trail. Should he drink once more of the river? Maybe rest a while and think about this? The forest didn’t seem quite so creepy now.

The voice he heard forced his hand. It came from the rift at the top of the trail – an indistinct grumbling, getting closer, and definitely headed in

Nico’s direction. Whatever it was, Nico estimated it was only seconds from appearing, seeing him and blocking his only exit.

With no other option, he darted through the archway, ducking to one side behind the nearest cover he could find: a tall tree with bark as black as night. Beyond, in the gloom, was an area that looked like an overgrown garden.

The voice got louder. Nico hid behind his tree just as something emerged from the archway. It was as if all of Nico’s blood instantly chilled, and

when he slowly let out a breath he could see it condensing in the air. ‘Mother, she’s intolerable!’ said the voice. ‘Why do we have to listen to

her?’

From deeper in the garden, another voice answered. It must have been Mother – and her tone was harsh and unforgiving.

‘I don’t know why my children are so disobedient,’ she said. ‘I created you. I gave you life, I gave you purpose, and what do I get in return?’

There was a terrible pause.

Then the first voice said, ‘Love and affection?’ ‘Disrespect!’ shrieked Mother.

Nico moved slowly, turning his head until his right eye could just peek around the edge of the trunk. What he saw twisted his heart around his

stomach.

Mother was enormous, at least three times the size of an adult human.

She was swathed in smoke and ash that swirled around her like she was the eye of a hurricane. Her dress was the deepest black Nico had ever seen, glittering with the twinkles of entire galaxies. Her face was an indistinct mass of darkness, but her eyes burned with the fury of twin supernovas. She sat on a Stygian iron throne at the centre of a circle of black trees. Dark gravel paths wended between topiaries that looked like clouds of ink –

every branch, leaf and flower competing to be the darkest thing in the

garden. And in the distance, at the edge of Nico’s vision, rose some kind of onyx structure – perhaps a temple or a palace.

The other figure stood before Mother’s seat.

He was tall but more human size, with a dark skin tone and shoulder-length black braids. He wore a sweeping black coat that shimmered in mesmerizing patterns, making Nico’s eyes feel heavy. ‘No one is disrespecting you, Mother,’ he said, his tone guarded. ‘But Gaia is not our master. Why should we –?’

Mother unfurled a set of wings that stretched from one end of the tree

circle to the other. Their leathery surface swirled with shadows. ‘Must you always disagree with me? After that last debacle with Kronos – which I told you not to get involved in – you wouldn’t even be safe if I hadn’t let you

stay here, Hypnos!’

Involuntarily, Nico grunted with surprise. The god Hypnos – who had put the entire island of Manhattan to sleep during Kronos’s assault on Olympus – apparently lived here now, in his mother’s basement?

Mother’s wings quivered, dripping liquid shadow from their spiny tips. ‘We are being watched,’ she said.

Her terrible eyes scanned the area where Nico was hiding. He jerked back and dropped to the ground, his heart racing.

He couldn’t get caught. Not this close to the end. And he had to be close! He’d done as Nemesis told him and followed the River Phlegethon. Unless Nemesis had guided him into a trap …

Nico stayed as still as possible. The archway he’d entered was only a few steps away. Maybe, if he sprinted, he could get through it, back up the path and into the forest.

He never got to find out. Tendrils of smoke wrapped around him and abruptly lifted him into the air.

‘No!’ he cried as he was yanked backwards across the garden, then spun around to find himself face to face with her.

Up close, her visage wasn’t just dark and indistinct. Except for those piercing eyes, it was a churning void, a black hole devouring all light and matter. It was pure hopelessness made real.

‘Now, who are you?’ Her supernova eyes seemed to be peeling back

Nico’s soul layer by layer. Her swirling debris-cloud of darkness held him fast, but Nico didn’t struggle – he suddenly didn’t want to. He was paralysed.

‘I asked you a question,’ she said, and her voice had gravity, as if it might pull the answers right out of his skull.

‘Mother, leave him alone,’ said Hypnos with a tired sigh. ‘It’s clear that he’s harmless.’

‘Harmless,’ Nico echoed, exhaustion spreading through his bones. ‘Definitely harmless.’

‘Hypnos, stop feeling sorry for him!’ Mother commanded. ‘Why are you always taking pity on every stray you find?’

‘Sorry,’ Hypnos said, lowering his head.

Mother pulled Nico closer, and he swallowed a scream. He’d never been so terrified, and yet he couldn’t fight, could barely even think.

‘You aren’t a monster,’ she cooed softly. ‘And you aren’t a god.’ ‘I could be …’ he said dreamily.

‘The god of bad decisions, perhaps?’ Mother sounded amused by her own joke. ‘Because you made a mistake coming into my home.’

Nico felt his rage stirring until he thought his heart would burst. He hated being confined, and he hated being ridiculed. But he couldn’t move. His

eyelids were made of lead.

‘How did you get here?’ Mother mused, looking him over like he was a specimen of some invasive species. ‘This realm is protected from all who don’t belong. Unless … ah, a demigod.’

Nico smiled weakly. He tried to look smug and unconcerned, but he doubted he was pulling it off.

‘You got me,’ he said.

She cackled, her voice radiating malice. ‘You are terrified, child. As you should be. Fear is the highest form of respect you can give me.’

‘It is best to stay afraid of Nyx,’ grumbled Hypnos from somewhere behind him. ‘I’ve certainly learned that.’

Nyx.

Nico hadn’t heard that name in ages, but he knew her by reputation. She was the goddess most other gods were terrified of. No one ever risked making her angry; even Zeus refused to mess with her. She was the goddess of night, born from Chaos, and one of the original inhabitants of the universe.

Now he understood Nemesis’s warning to be wary of her mother. Nico had come to Tartarus looking for a way to stop Gaia from rising … and he’d

walked straight into the lair of a goddess who was just as old, powerful and dangerous.

‘I see you are putting the pieces together,’ said Nyx, her voice thick with amusement. ‘No need to explain your parentage. I’ve already figured it out. There is only one father whose children could survive this long in Tartarus. And there is only one reason the entrance to my home would reveal itself. It sensed a kindred spirit …’

The darkness swirled tightly around Nico, pushing all the blood to his head.

‘What an interesting case you are,’ Nyx continued. ‘A son of Hades, yet you live in the mortal world, don’t you? I can smell the stench of daylight on you.’

Hypnos tutted. ‘Oh, Mother doesn’t like that.’

‘I don’t like that,’ she confirmed. ‘Do you know why, son of Hades?’ Nico had to use nearly all his energy just to shake his head.

‘We are all born into our own natures,’ she said. ‘I, created from Chaos, was given unto the night. It is what and who I am. Who are you, Nico di Angelo?’

He gasped softly. ‘How –?’

‘How do I know your name?’ Nyx feigned outrage. ‘We are in Tartarus, you silly child. Everything here is stripped to its truest, rawest form. The longer you remain with me, the more clearly I can see you … and the less you can hide.’

She brought Nico so close he thought he would pitch forward into the void of her face.

‘Have you ever looked at yourself, Nico? Because I see the truth. You belong down here in the darkness. It is your nature, and yet you fight it every day. Must you be so obstinate? Must you ignore the obvious?’

‘No,’ he said, squirming against Nyx’s hold. ‘I know where I’m supposed to be.’

A terrible laughter echoed from the empty space where her mouth should have been. ‘You are hopelessly confused. Those who are confused end up with me.’

‘They do,’ said Hypnos. ‘They always do.’

‘Night is when all beings stumble and go astray,’ Nyx said, her voice now soothing, ‘but it is also when you can face the darkest truth. You must stop entertaining this notion that you can escape who you are. I will help

you choose, Nico di Angelo. I will make things so much simpler …

Choose.’

Her last word was a blast of darkness, and Nico could feel his soul breaking into dust, his identity being shorn away and pulled into Nyx’s gravity. He couldn’t breathe; hopelessness radiated through every part of his body; he believed this was the end.

Which was precisely when the giants arrived.