The Underworld… the Land of Bliss… the final resting place of heroes' souls!
That's it. That has to be it!
A sharp glint flashed through Samael's eyes. He slapped his forehead as everything suddenly clicked into place.
Paradise Island did not necessarily have to be an island at all. It could simply be a regional name based on environmental characteristics. Ἠλύσιον—Elysium—was likely its true name.
Likewise, Paradise Island did not have to exist on the sea or in the sky. It could very well be located within the Underworld.
After all, if the goal was to bind the souls of heroes to a specific land, nurture them, and put them to use, what place could possibly be more suitable than the realm of the dead?
What's more, in the Mesopotamian world, he had once established [Paradise Lost] in the deepest layer of the Underworld to house the souls of fallen Uruk warriors. Functionally, it was strikingly similar to Paradise Island.
A blind spot. A complete blind spot.
How had he gone in circles for so long without realizing something so obvious? Samael felt a surge of annoyance at himself.
Nearby, Little Medea, who had been sneaking glances his way, saw the Ancient Serpent's rapidly shifting expression. Unease welled up inside her. Looking dejected, she lowered her head, her words coming out haltingly.
"Th… Theseus-sama, did… did I say something wrong? I'm sorry…"
"No, no! Medea, you were a huge help. On this Argo expedition, compared to some lifeless Golden Fleece, your knowledge is the most valuable treasure of all."
Samael snapped back to himself, immediately placing his hands on the girl's shoulders and looking at her seriously, offering praise without restraint.
I'm… the most valuable treasure? More precious than the Golden Fleece? He came all the way to Colchis for me…
So this is how Theseus-sama sees it. I'm so happy!
Her emotions swung wildly. Love-struck and overwhelmed, Little Medea's cheeks flushed bright red, her eyes sparkling with joy and shy delight.
Completely unaware that a certain young girl had already written tens of thousands of words of youthful romance in her head, Samael was in excellent spirits now that the true location of Paradise Island had come into focus.
"If Elysium really is Paradise Island, then we'll have to make a trip to the Underworld. The question is, how do we get there?"
Just as hope emerged, Artemis frowned, voicing the immediate problem even as she felt relieved.
The Sky gods and Sea gods at least had some interaction with one another.
But the gods of the Underworld were a closed system, largely cut off even from Olympus itself. Only a handful of deities with special permission could pass freely.
And the Moon Goddess herself was not among them.
"Don't worry. I have a way."
Samael smiled and raised his right hand reassuringly, clearly confident.
He then entrusted Artemis to Atalanta's care, stepped out of the hall, spread his wings, and flew straight toward Thetis Island.
...
"You want me to open the entrance to Tartarus?"
Inside the towering palace, Poseidon sat high upon a throne carved from an entire coral formation, inlaid with gemstones and pearls of every color. Hearing this request from his former opponent, his brow immediately tightened.
"Paradise Island is very likely hidden beneath the Tartarus caverns, on the desolate plains of the Underworld's riverlands. If this hidden danger isn't eliminated, Areopagus will have to reassess the odds of that operation.
"After all, you're Zeus's brother. Even if something goes wrong, the worst that can happen to you is being locked in Tartarus. We might not be so fortunate. We're responsible for our own lives. We can only succeed. Failure isn't an option."
After relaying the information obtained from Medea, Samael stood below the throne and made his stance clear, deliberately applying pressure.
There were two reasons he had come to Poseidon regarding the Underworld.
First, the Ancient Serpent had personally witnessed the war between the old gods of Mount Othrys and the new gods of Olympus, fought across the Oceanus Sea. The three defeated Titans had been dragged through the sea and cast into the Tartarus caverns of the Underworld abyss.
Second, according to the records of the Theogony, Tartarus was surrounded by three layers of darkness and three bronze walls. Its bronze gates were forged and guarded by Poseidon himself, while Hades presided over the Underworld.
In other words, Poseidon held the key to entering the Underworld from the sea.
At this point, they were all on the same ship. If Paradise Island was truly Zeus's trump card, destroying it would benefit both sides. If not Poseidon, who else could he turn to?
At the same time, Samael's uncompromising opposition toward Olympus seemed to ease Poseidon's mind instead. His expression relaxed slightly.
Opening the entrance to Tartarus did carry risks, but Poseidon preferred allies who were fully committed to confronting Zeus head-on. Otherwise, what was the point of all the effort he had put into winning over Areopagus?
After a moment of thought, Poseidon spoke, offering his answer along with conditions.
"I can help you open the entrance to Tartarus. But it won't stay hidden for long. Zeus will definitely notice. I'll wait three days at most."
"Three days is too short. We know nothing about the actual situation in the Underworld or Paradise Island. To get real results, we need at least seven days."
"…Fine. Seven days it is. But once those seven days are up, whether or not Zeus's trump card is destroyed, Athena must ascend Olympus with me."
This…
Just as Samael hesitated, the olive branch placed in a vase beside Poseidon suddenly began to glow. A radiant shimmer spread as Athena's projection emerged, her voice solemn.
"Agreed."
Only then did Poseidon nod in satisfaction, sealing the agreement with his powerful niece.
Seeing that the matter was settled, Samael shot Athena's projection an annoyed glance, then resigned himself to the outcome.
"Time is tight. Make your preparations first. I'll join you shortly."
When it came to plots of usurpation and kingship, Poseidon acted decisively. With the details finalized, he moved to dismiss his guest.
"Wait."
Just as Samael was about to leave the hall, the Sea King seemed to recall something. He called out, his eyes flickering as he spoke quietly.
"You're going to the Underworld anyway. Take this with you."
The Ancient Serpent reached back and caught a pale blue piece of amber tossed toward him. As he opened his hand to examine it, his eyes narrowed slightly, a playful smile curling at his lips.
Inside, light seawater gently swirled. On the dream-inducing seabed within, Briareos lay fast asleep in a drunken stupor, his massive form shrunk down thousands of times.
It seemed the prisoners of Tartarus were about to gain a new cellmate.
Leaving Thetis Island in high spirits, Samael rushed back to the Atlantis reception hall to share the good news with his companions from the Argo.
"Um… can I drop out?"
Just as the cheerful atmosphere was reaching its peak, an arm rose hesitantly from the crowd, the question tinged with awkwardness.
When Samael's gaze shifted over, the crowd instinctively parted, revealing the figure of the ship's captain, Jason.