Elysium- 10 years later

The sound of laughter and happiness filled the grassy playing field. Children ran around with each other whilst teens were playing sports or walking around together. This very place looked to be heaven but the look on one young man`s face did not.

He wore a deep scowl and you would think the influence of his two friends, who were almost identical to him, would help his mood but it did not. The three friends were walking near the shade of a giant oak tree when the slightly older boy pulled the boy with a bow across his shoulder to the side.

"Orion, he is not getting happier. He is becoming battle-hardened and warrior-like. It is a good thing he is dead because if he was not, he would have died long ago."

"Leave him be brother," Orion said, "He may look unforgiving but he is in mourning. We all know how that feels Theseus." He gave the older boy a knowing look and walked off to his younger brother.

The underworld- Hade`s palace.

The god of the underworld sat on his throne looking into a glass ball. The image seemed to show Elysium, or more specifically the three sons of Poseidon. The sound of heels clicking against the floor of his marble throne room broke his gaze away from the ball.

"Have you found anyone to help you against the threat?" The beautiful women wearing a dress that showed all the colours of a rainbow said.

Hades gave a wry smile. "It seems as I have, my dear Persephone. I wanted two close demigods. I got 3 but the only thing that I didn`t want was to have a son of Poseidon assist me, let alone three."

Persephone gasped, catching on to what he was saying. "You will be punished for breaking Zeus's rules. You of all people should know that Hades."

"Well if I don`t. Zeus will be in more trouble than ever before and the world will be doomed." Hades replied one final time before looking back at his glass ball.

Elysium

It felt like hours since Theseus and Orion had their talk about Percy, you really couldn`t as it was always sunny, and the three teens were sparring with wooden swords and spears by a large palace. It was Orion and Percy against Theseus and they kept rotating every time one got defeated. They were interrupted by a loud flapping of wings and they looked up to see a man with dark skin and even darker wings swooping down on them.

Percy was the first to speak. "What do you want here, Thanatos."

"Hades requests your assistance." The death god replied, motioning to the portal which appeared with a wave of his hand.

Theseus grabbed his two brother's arms and began whispering. They seemed to have agreed on something.

"We will go with you to Lord Hades palace." Orion declared and they marched into the portal.

Hades palace

The other end of the portal ended right at the entrance of the throne room doors. Just as Theseus raised his hand to knock, a powerful voice bellowed at them, "Enter!"

They pushed the doors and approached the god of the underworld. He wore Pitch-black robes that contrasted with his pale skin. The souls of cursed mortals moaned and groaned in his robes. He sat 15 foot tall on his throne of bones.

"Sons of Poseidon," he began, "I need your help. A new threat is arising and it begins here, in the underworld. I want you to battle it`s forces and stop it before it takes over my domain and marches onto Olympus otherwise everyone`s doomed."

The 3 teens were in shock before Theseus spoke up, "What is this threat."

Hades sighed. "Erebus. Primordial of darkness; the very personification of darkness. Gaea`s attack has awoken Erebus and he wants to take back the world."

Percy narrowed his eyes. "How are we going to help, we are dead."

Hades stared at Percy. He has grown mature and bitter. "I am willing to bring you back alive, you will not change one bit and you will assist my son Nico to stop Erebus. Do you accept?"

The sons of Poseidon began to huddle up before they turned to Hades and said in unison, "We accept."

"As long as you don`t tell those gods about us." Percy added.

Hades nodded and then stood up and began chanting in ancient Greece and the 3 teens looked at their faint muscles as they slowly began to become real.