Grover and Eurydice stand outside the mattress store while Percy and Annabeth clear the way and find the entrance to the underworld. 

Eventually, after getting bored of waiting and hearing some yelling inside the store, Grover pushes open the door open.

"Is it over?" He asks. 

The other two nod and Eurydice and Grover enter the store and all four of them walk to the back office.

"Are we sure this is the right way?" Grover asks nervously. 

They walk up to a lone door in the office pushing it open hearing wind whooshing through and a foul smell hits them.

"It's either the realm of the dead, or someone left a carton of milk in there in the 1990s." Percy jokes.

Annabeth picks up a stress ball off the desk handing it to the anxious satyr. Grover takes the ball squeezing it in his hand, the ball lets out a loud squeaking noise. 

"Better?" Annabeth asks.

"Much." Grover responds.

"If we get into trouble..." Percy holds his hand out showing five pearls, "...these are our tickets out."

"No one's turning back till we all come back." Annabeth protests not taking a pearl.

"No one comes back." Procrustes calls out from where he's trapped on the bed. 

"Dude! Don't make me come back out there." Annabeth yells at him.

"We have no idea what's down there." Percy says, "I just think it's safer if I'm not holding them all." 

The other three concede each grabbing a pearl from Percy's hand. 

Grover squeaks the ball again, "Let's go get your mom." 

The four of them enter the door, Grover walking slowly behind with Eurydice in front. 

"Grover," Annabeth says, "Hurry up!"

"Not in Kansas." Percy mutters under his breath.

"Hey, focus." Annabeth turns to him, "We left Kansas four days ago."

"Yeah. No, it's a..." Percy cuts himself off pointing to a cloaked figure a few feet away, "Never mind. Guys, is that who I think it is?"

"Charon, the boatman," Eurydice answers, "taking new arrivals across the River Styx."

"Which means that over there is the main gate." Annabeth points across the river.

"Let's go." Percy says, "Maybe we can get there first."

"Yeah." Annabeth agrees. 

Grover squeezes the ball repeatedly causing the loud sound to ring out in the quiet "lobby" of the underworld. 

"Why don't you let me hang on to that for now?" Annabeth holds out her hand taking the ball from Grover. "Come on."

The four of them weave their way through the long line of people awaiting entry to the underworld. 

"This seems so wrong." Grover points out. 

"Nah." Percy jokes, "Only suckers wait in line."

"Just..." Grover protests, "You know, you should really spend some time in the city with me. I think you'd learn a lot."

All of a sudden the same cloaked figure, Charon, stands in front of the four. 

"You're not dead." He says ominously. 

"I mean... we're all dying... to some extent." Percy rambles.

"And you didn't pay to cross."

"Wait!" Percy calls out stepping up next to Eurydice, "We... we can pay! We can pay!"

He unzips the backpack pulling out some of the drachmas Ares gave them. 

"Here. Drachmas." He holds some of them out, but gets ignored.

"Just take... take, uh..." He pulls out more cupping them in two hands and Eurydice rolls her eyes at him, "Just, you know, take them all."

"I'm here to see my mother," Eurydice speaks up stepping forward. 

"Your mother is not currently in the underworld, and even if she was I promise you she does not want to see you," Charon responds coldly before grabbing the whistle around his neck and blowing into it.

"You can buy a new whistle," Percy says still holding out the drachmas, but Eurydice's face falls knowing what that whistle means. 

"Shit!" She calls out, "Run!" 

The group looks at her confused before they see Cerberus approaching from the fog around them. 

"Go. Now!" She tells the other three pulling out her sword, so they could keep going. 

"We're not leaving without you," Annabeth protests and Eurydice sighs knowing there is no changing her mind, so she takes off in a run behind the other three half bloods. 

As they're running one of the dog heads grabs Grover.

"Grover!" Percy calls looking back, but Eurydice forces him to keep running. 

They keep running until they reach a dead end. Annabeth jumps onto Cerberus and manages to scratch behind his ear causing him to calm down and fall asleep.

As Cerberus snores, Grover falls out of the dog's mouth covered in slobber. 

"You... are a bad... bad dog!" Grover scolds.

"Guys! I can't hold this forever." Annabeth warns.

"Can you fly us up there with your shoes?" Percy turns to Eurydice who nods slightly.

"You can do this." Annabeth reassures the older girl, "One at a time. Take Percy first. Then Grover."

"Maia," Eurydice says grabbing both Percy and Grover at the same time instead of one at a time, determined to be able to save Annabeth as well.

She strains with the weight of two people on the shoes, but eventually makes it to the top of the cliff setting Percy and Grover down. 

They hear Cerberus roar and run over to the edge. 

"Annabeth!" They all call out looking over the cliff.

All of a sudden the red ball comes flying up over the cliff and Percy catches it. The ball squeaking as it lands in his hand. The three of them jump back when Cerberus jumps up trying to bites at them, but missing. 

"Guys?" They hear from below. They rush over the the edge, seeing Annabeth clinging to the side of the cliff.

They rush to help her, pulling her back up onto the cliff with them. 

"Wow." Grover says in awe of how she handled Cerberus, "That was really... I mean, how did you?"

Annabeth cuts him off, "My father had a dog when I was little. I guess I remember the tricks."

"Oh, wow." Eurydice says staring off in the distance grabbing the other three kid's attention, "Look at that."

"Hades' palace." Annabeth says, "That's where he'll be keeping the master bolt. And your mom."

Grover feels around in his pockets anxiously, "Oh, no."

"What?" Eurydice asks.

"My pearl. I lost the pearl." He explains nervously, "I think it's..."

He pauses.

"It's in the dog."

"What are we gonna do?" Grover worries.

"I don't know." Annabeth says hearing Cerberus following close behind them, "But if we don't move, it is not gonna matter. Come on."

The four continue walking moving towards Hades' Palace. 

"We can't ignore this." Grover stops them.

"Stop." Percy insists.

"It's just math." Grover says, "The four of us, plus your mom, is five people, and only four pearls. Someone is staying behind and it should really be me."

Percy sighs, "It wasn't your fault."

"And even if it were, you're not getting left behind. Period." Percy reassures the satyr. "After we get the bolt and stop this war, you guys are leaving."

"With my mom."

"What about you?" Eurydice asks, knowing she won't like his answer, "Wait, wait, wait, Percy. What about you?"

"Quests aren't linear, right?" Percy answers, "I'll figure something out..."

The four continue walking, a weight settled over all of them now. Percy walks into a person standing in a field and hastily apologizes receiving no response. 

"They can't hear you." Annabeth tells him.

"They?" Percy questions. 

The four of them look around seeing more people standing with blank expressions all around them. 

"This must be Asphodel." Annabeth tells them, "I read a book about this place."

Annabeth moves to lift the dress at the bottom of the figure.

"Wait. No, no. No, no, no, no, no. What are you..." Percy protests before seeing what Annabeth was looking for.

"Are those roots?"

"Souls here are bound by regret." Annabeth sighs dropping the fabric.

"Haunted by choices they made in life," She explains, "or never made." 

Cerberus lets out a load roar from the distance and the four know they have to keep moving. They start to run, but stop after a little while when Annabeth suddenly stops. 

"Annie?" Eurydice asks turning to face her.

"Guys!" She calls out gesturing to the roots attached to her feet.

"Annabeth!" Eurydice cries.

"We've got a problem here." Annabeth tries to joke, but it falls short. 

Percy, Grover, and Eurydice try to tug on the roots to free Annabeth.

"I already tried." She says sadly, "It's too strong."

Percy begins to panic, "How did this happen?"

"It's some kind of regret, right?" Grover says, "But what would you have to regret?"

"It's okay." Annabeth ignores Grover's question, "Go. I'll distract the dog and buy you guys some time." 

Percy continues to strain trying to pull the roots from Annabeth's feet.

"Percy!" She yells causing him to stop. 

She holds out her pearl, "This will work. I'll be okay. I trust your dad. I trust you."

"You can do this." She tells all four of them, "I know you can."

Cerberus starts pushing through the trees getting closer to them.

"Run. Now!" Annabeth yells and the other three listen reluctantly. 

They start taking off. Eurydice risks a look back and sees Annabeth throw down her pearl before she disappears. 

"She made it," Eurydice lets out a breath she didn't even know she was holding. 

"Let's go!" Percy says grabbing her arm and pulling her to keep running with him and Grover. 

After a little while the three of them end up in what looks like a giant desert. 

"Weird." Grover speaks up, "Haven't heard the dog in a while." 

"He chased us all that way and then just... stopped? I wonder why." Percy stops, looking back trying to see if he can see Cerberus anywhere.

"That's what I'm saying." Grover agrees, "It's weird."

All of a sudden the shoes on Eurydice's feet activate, the wings popping out and fluttering pulling her across the sand. 

"Eurydice," Percy calls chasing after her, Grover following the two. 

"Eurydice, where are you going?" 

Eurydice begins to panic, "I don't... I don't know. I... I can't stop!" 

"Percy! It's the shoes!" Grover tells Percy trying to help him grab Eurydice. 

They see now that she's being pulled towards a giant crater in the sand.

"Eurydice!" Percy yells holding out his hand. 

Percy and Grover each take one of Eurydice's hands and try to find some place they can grab onto before they fall into this vortex, but all they are met with is sand slipping through their fingers. 

Suddenly Percy unsheathes his sword sticking it into the sand and using it as an anchor. The shoes keep trying to pull Eurydice, but now all they manage to do is loosen and fly off her feet into the pit. 

The three of them collapse onto the sand and pant heavily. 

Percy falls backwards his backpack hitting the ground with a loud clanking sound. He furrows his brow pulling his bag off and opening it. 

He pulls out a large metal object apprehensively. 

"Is this..." He asks holding it out to the other two.

"No." Grover cuts off quickly.

"I mean, it looks like..." Percy argues.

"It absolutely is not." Grover says.

"Okay." Percy concedes, "So, what is it then?"

"Yeah, that's the master bolt." Grover says quickly.

"I mean, I think so, right?" Percy nods.

"How is it in your bag?" Eurydice asks, knowing that Percy is definitely not the lightning thief.

"Wait," Percy realizes, "this isn't my bag."

"This is the bag Ares gave me."

"Ares had the master bolt this entire time and tricked us." Grover says.

"He was working with Hades?" Eurydice asks confused.

"I guess so" Percy says. 

"I mean..." Grover says softly, "that was it, right? That's the quest."

"Zeus is expecting us to return this." Eurydice motions to the bolt, before she sees Percy looking out across the desert to Hades' palace.

"Zeus is just gonna have to wait." Grover says. "Let's go get your mom." 

The three of them walk through the entrance to the palace.

"Hey, fellas. Welcome!" Hades stands there waiting for the three. "Sorry about all the... Oh... Anyways, it's great to meet you."

Eurydice eyes him before looking around the rest of the palace taking in her mother's home and the man she loves so dearly, that she abandoned her and her father. 

"I know who you are, and you know who I am, so we can just skip right past that part." Hades looks over the three half bloods, "Can I get you anything?"

"Fresh pomegranate juice, a snack?" He directs that comment towards Eurydice and she rolls her eyes. "Actually, if..."

Percy steps forward cutting him off, "My mother." He stares Hades down.

Hades raises and eyebrow, "Boom. Straight to business."

"I admire the cut of your jib." He tries to joke but no one laughs, "Little nautical reference for you. I see you."

Percy rolls his eyes, done with Hades, "Where is she?"

"Right. Okey-doke." Hades turns around gesturing to a bronze statue, "Let's get to it. Your mom's just over here."

"You've come all this way, don't be shy." He steps out of their way and Percy moves towards the statue of his mom. 

"Mom?"

He turns to Hades angrily, "What did you do to her?"

"Uh..." Hades scoffs, "Saved her life?" 

"You know, typically, getting crushed by a Minotaur is a terminal diagnosis." Hades deadpans, "I snagged her for ya, just in the 'ta-da' nick of time, so that you would come see me. And here we are."

"Are you expecting a thank you because I don't think you'll get one," Eurydice snaps. 

Hades brushes her off, "You give me what you got, and I'm giving you what I got."

"I..." Percy hesitates, "I can't give it to you."

"Ah, see, there's a quid and a quo here." Hades tells them.

"The bolt doesn't belong to you." Percy tells him, "Your plan almost worked. You and Ares managed to steal the bolt, trick me into bringing it right down and giving it to you. But it's wrong, and I won't do it. So all I can do is ask you to do the right thing, too."

"Please..." He begs, "let my mom go."

For a moment Hades looks genuinely confused and it catches the three half bloods off guard, "Huh?" Hades asks. 

"What?" Percy asks back. 

"Who... who tricked Ares into doing what?" Hades asks.

"You're in cahoots with Ares, to secure the bolt." Percy tells Hades although less sure of himself now.

"I'm not in cahoots with Ares." Hades argues, "I seldom 'cahoot.'"

He turns and winks at Eurydice, "Except with your mother." 

Eurydice shudders at the thought. 

Hades turns back to Percy and continues, "The bolt is my brothers' drama, I don't want any part of it."

"You don't want it?" Percy asks, now completely lost.

"No." Hades insists.

The three share a confused look.

"Then what do you want?" Eurydice presses.

"My helm!" Hades exclaims.

"Your what?" Percy asks.

"My Helm of Darkness. It went missing just days before someone used it to turn invisible and steal the bolt." Hades explains, "I'd like it back now, please, and then you get your mom back."

"You really don't want the bolt?" Percy asks again, still not grasping what Hades is saying. 

"Why would I want that?" Hades asks.

"To start a war between your brothers." Percy tells him.

"Why would I want that?" Hades repeats again.

"Jealousy." Percy responds simply.

"I don't know if you noticed, but it's all candy canes and rainbows down here." Hades counters, "I'm managing just fine. I don't really do jealous. My brothers, on the other hand, have the market cornered on jealous. Family drama is why I don't go up there anymore. These grudges, they go on forever. Super unhealthy."

"Someone stole Zeus's bolt, it wasn't me, it must have been somebody who was..." Percy begins before figuring it out, "Kronos."

"Excuse me?" Hades turns to Percy angrily at the mention of his father. 

"He's got the longest grudge of them all." Percy explains. "Zeus took Kronos's throne. Who else has a bigger reason to weaken Zeus and take his throne back?"

"Kronos is in a million pieces at the bottom of..."

"Tartarus, where something just tried to pull us into it the moment the bolt appeared in our bag." Percy tells Hades, "Tartarus... where I've been hearing a voice from in my dreams, telling me it needs my help to take down Olympus."

"I assumed that was you, but that voice I heard... that definitely did not sound like you."

Hades lets out a sigh.

"Ask me for sanctuary," He tells the three.

"Excuse me?" Eurydice asks offended. 

"If Kronos is somehow planning to emerge from his exile, and you were his first call... you're not safe." Hades tells Percy, "Ask me and I'll protect you. You and your mother." 

Hades then looks over at Grover and Eurydice, "And the goat and girl,"

Eurydice rolls her eyes muttering under her breath, "We have names you know, and I know for a damn fact you know mine."

Hades ignores her comment smirking, knowing he's gotten under the girl's skin. 

"I'll throw them in, on the house. This works out nicely for you as it turns out. All it'll cost you is the bolt."

"I thought you didn't want the bolt?" Percy challenges.

"I don't want the bolt." Hades answers simply confusing the three, "Now, I need the bolt. If war with Kronos is coming, I'd like to be prepared."

He holds out a hand to Percy, "Not messing around here, kid. This only ends one way. The only question is how difficult you make it."

"No." Percy says hugging the backpack tightly to his chest. 

Hades steps closer to Percy, "Give me the bag."

Percy pulls out his pearl gesturing for the other two to do the same.

"Nice pearl." Hades comments.

"I accept your offer." Percy tells him. 

"Great!" Hades tells him opening his hand for the bolt. 

"Your first offer." Percy challenges, "We're gonna go get your helm. And when I get back, you're gonna let my mom go."

"Okay. Hang on, kid." Hades goes to protest.

"Grover, Eurydice, now!" Percy yells and the three of them throw their pearls against the ground. 

"Hold fast, Mom." Percy sends a look back to his mom, before they all are teleported back to the beach. 

Eurydice falls face first into the sand standing up slowly, seeing Percy, Annabeth, and Grover standing there together. 

"Let's fight a god," Eurydice smirks over at the three before walking over to them drawing her side.

"Hell yeah!" Percy agrees.