The entrance lobby was quite nicely decorated. Too much gray, but it was classy and elegant. Neptune approves.

At least he's being helpful with his notes.

The Trio walked up to Charon, but whatever hope Neptune has was dashed when Percy open his mouth.

"Your name is Chiron?"

Perseus, use your common sense! Who else who named similar to that ol' centaur but has no equine body part?! Surely, you've learned about it!

If anything, that was first red flag that Charon got living visitor to Underworld. Thankfully he was feeling in good mood that he merely corrects the pronunciation. Also… how often are ghosts screaming to be allowed to go back to the world of living? Too often? What would he do if one ghost didn't bother begging and just… walks out? Can they do it? So many questions Neptune had about how his elder brother running his kingdom.

"How did you die, then?"

Oh. He ask that question, too? Neptune didn't know Charon make idle talk. He thought the ferryman just ask for coin and take them down.

"Oh. Um…" The Faun stammered. "Drowned…" yes. The Mississippi river can be quite deep. Especially after someone JUMPED FROM SIX HUNDRED FEETS IN THE AIR! "In the bathtub."

…

Backtrack on that. What?

"All three of you?"

Surely they cannot be that—

The trio nodded.

THUD!

Neptune slammed his head to the nearest wall. Despairing at their collective intelligence.

Out of all excuses… why it have to be THAT IDIOTIC EXCUSE?! Perseus' Circus Caravan story sounds leagues better compares to this! Come on child, there are more believable excuse! The white lie! Two of you could claim running afoul at Procustes—which you are! Just show the strain marks on your wrist! Perseus should have corrected it and said drowned in Mississippi river after having a terrorist blow up a national monument. Or at Love Tunnel in Denver! Hell. Staying underwater too long at Santa Monica beach also works! One of them is Minerva's spawn but she didn't bother to corrects them either.

Augh. This idiocy hurts him.

At least Perseus shows his cunningness, in how he plays by Charon's nature. That was something Neptune approve of.

With one last promise, something about pay raise, Charon was defeated. "It's almost full. Suppose I can add four more."

Four? Aren't there only three?

"Aren't you coming, sire?"

Neptune lifted his head.

To his astonishment, Charon's eyes completely fixed at him.

"…me?"

Charon raised an eyebrow.

"Of course, who else. Aren't you come with them?" Charon ask, mockingly. "Quite a group you made. My, I have meet quite the number of your children yet this is the first time I see you following after them like persistent shadow. Now, don't waste—"

Charon's hand passed through Neptune's shoulder.

Silence.

"…well. Now that is interesting." The Daemon hummed. "I have never seen a being I can't touch."

"I am not normal spirit." Neptune clarified.

"I know."

"I am… don't even know what state I am."

"Oh you don't. That's for certain." Charon nodded. "Which make it all more agreeable that I let you come. I believe your brother would like a chat. He had been… wanting to talk to you lately. Something about Tartarus or the like. What did you do, hm?"

…Pluto would've sense Poseidon, then. His other half doesn't know the meaning of Subtle when his children are involved. No. that was his Salacia's duty.

Charon pulled a note and a pen from behind the counter, and write something.

"Let's go."

Awkwardly, Neptune follow after the daemon. He was seated close to the Daemon as to not eat too much space. The living ones did not see him (because otherwise Perseus would raise questions—that child inherit Poseidon's mouth for certain), and the dead ones busy with their own business.

The state of River Styx made Neptune want to hurl.

It was oily, full of trash. Things that could've been treasured gift, once was treasured gift, but now are tattered and nothing more than pollution. It was filthy and the mere state of it make Neptune seasick—and as God of Sea, thanks to Poseidon's powerful influence, he is not supposed to ever have seasickness.

"Father please let me go out alive, please let me save my mom."

Neptune heard that Prayer. Normally it was foolish to pray as neither he or Poseidon has clout in Underworld. Now that Neptune sit two rows behind Perseus, maybe it was not that foolish.

Maybe.

Soon enough, they reach the other riverside. The living ones dismounted first. Then the dead.

Neptune was held back with Charon raise hand to stop him.

"The Three Face is hungry." Was the ferryman said, as a (hungry) howl could be heard. "Best of wishes, Godling. I'll be hurry if I were you." He nearly hit the Faun as he pushed them to move.

After a while, and making sure they were out of sight, he finally allowed Neptune stepped on the riverbank. Just in time as a hellhound trotted to them.

"Take this to Lord Hades." He give the note to the hound. "And you better follow him. No straying from the path unless you want your godling in danger."

Having no choice, Neptune followed the hellhound. Perseus and his questmates already pass, with the Cerberus whimpers with a tattered, positively soaked with droll, rubber ball near the guard dog's feet. He patted the leg and use bit of power he had to restore the ball to good condition.

He thinks the Hellhound is whimpering in jealousy?

It still led him pass the Judgement Hall. Having Hellhound as tour guide give Neptune the benefit of bypassing the line. A VIP Treatment. The judges raised an eyebrow at this, but otherwise they did not say anything. Merely continue with their business.

Neptune did not like Minos, though. He's convinced it was due Poseidon's influence, but he can't help asking question why is that horrible man made the judge of the hell? He's manipulative bastard who can't keep his promise. Granted said broken promise led to Theseus' fame, but that boy is famous already without it. And Minotaur's existence bring pain to their Perseus and his mother.

Bottom line: he did not like Minos and would gut him if given chance. Keep them apart.

When he exited, he cannot help but glance around a little.

The Field of Punishment is horrible, but a necessary evil, otherwise evildoers in life won't learn their lesson and their victim won't get their due. Just that, the Off-Key Opera Song is terrible for his eardrums.

The Field of Asphodel is depressing. Period. Also… what with that size? Has his brother's kingdom inflated that much over the course of millennia? It was… horrifying. Moreso because Neptune and Poseidon had hands in that.

The Elysium is pleasant to look at, and made Neptune wondering, if his kids made it there or if they end up in Field of Punishment. Unlike Poseidon, he is not blind to his children's faults. They were capable of making mistakes, and some of it has devastating consequences that positively earn them a spot in Field of Punishment. It was only matter of question whether their good deeds are more than enough to balance it or not.

The Tour is over when he was led directly to the Throne Room.

"Poseidon." Plu—no, Hades. This is Hades. His brother's Greek half. "I suppose I should know you will pay me a visit after a stint near Tartarus at the other day."

Neptune resolved to give Poseidon a major headache for this. While wanting to protect Perseus is all good, his Greek half lands them in trouble!

"… Apologies." Neptune bowed. It irks him to bow his head, even to his elder brother, but he was in the wrong, as he is Poseidon's proxy; and the Roman's less than stellar treatment had broken his pride (they would pay for the humiliation, he swears). "But there is… special circumstances."

Hades look at him coldly. "And pray tell me," He leans forward, "what special circumstances that I must forgive this transgression?"

Neptune glanced at the hellhound. It trotted forward and drop the note to Hades' waiting hand.

There was a silence as the Lord of Underworld read the note. His eyebrow rose.

In blink of eye, he was in front of Neptune, and his hand stick through Neptune's chest, as if he was a mirage in the water.

"Can you please not?" Neptune stepped back. "It's weird and unpleasant."

"Ah. Pardon me, brother." Plu—Hades! It was Hades! Hades look apologetic for brief second. "It was not everyday I see Spiritual Apparition. Much less, one that can bypass ancient laws, and one that I cannot interfere with. Say, can you touch things?"

"…unsure. Perhaps? This is Underworld."

Plu—Hades summon a seat for Neptune to sit on.

"This explains why you can enter my kingdom without going through the main and only entrance." Plut—Hades reassumed his throne. "But why Tartarus?"

There's a pain in his voice and Neptune felt guilt.

(Neither him or Poseidon pay their brother attention.)

"…Protecting Perseus."

Black eyes blinked in confusion.

"…your spawn hasn't reach underworld by then."

Neptune take deep breath.

"S—Kronos is rising."

Once again, the throne room is plunge into tense silence. If Hades notice the slip, then he made no mention of it.

Neptune feels chill on his spine. As if something terrible is happening. Or about to happen.

"Elaborate." Hades growled out.

"The incident at the other day? It was to protect Perseus. The Titan King had awoken and seems to goad Perseus to be the keg powder to set off World War the Third. All to hide how our… sire… escapes from the Depth of Tartarus and amassing army. That thing is using image of Perseus' mother as bait for cooperation"

"How can I trust your words that your spawn is not double agent? Why I shouldn't just throw him down there? He was pulling his Satyr friend from failing to Tartarus as we speak."

The armrest shattered under Neptune's wrath.

"You didn't tell me."

"You give me no reason to."

Neptune growled.

Deceitful Greek!

No. Calm down. Hades think you are Poseidon. Held it back.

"Perseus is not the agent. If anything, he is pawn. You know how that creature is."

Hades pursed his lips. "Unfortunately."

"I assume your helm is also missing?"

The displeased look is all confirmation Neptune needs.

"On that Incident, previously, our… progenitor, was talking to his true minion. The real thief."

"Who."

"I do not know." Neptune confesses. "But I recognize the voice. It was one of the campers."

"Why I can't just destroy that place and kill everyone?"

"Aside from causing more workload to yourself?" Neptune gestured to the Field of Asphodel. "That would cause literally any other gods and goddesses to come after your head, brother dearest. Give me time. Once I recognize the owner of the voice, I shall give you the name. Swear upon Mother's Name."

Hades… didn't slumped, but it might be closest thing to it.

"I'll hold you on that." He glanced at the door. "Your spawn manage to escape the Tartarus entrance with his friends. He's getting closer."

Neptune understand what Hades is asking him.

"…I have been trailing Perseus few times in this state, but he had yet to notice me aside from maybe that Incident. Perhaps it was the state of Underworld and how it host the dead, the ghosts, that make it possible." Theorize Neptune. "May I ask help? I rather not meet Perseus just yet."

Hades snorted. "Isn't he your favorite?"

"Ah well." Neptune doesn't know how to answer that. Technically Percy wasn't his… but… "I think Fate is testing him. For when he was given escape method, in case things gone south, it was just enough for his group. Add with you hold hostage…"

"I see." Hades waved his hand. A door swung open from behind the throne. "You can stand there and listen in."

"…Thank you. Brother. I owe you one."

For listening.

Because Neptune just know that Jupiter won't.