Author's note:

xxOkunixx here! Welcome to [The Other Side]! Thanks to all those who voted this story to the top along with [Hunters vs Amazons] in my previous fanfic [Percy Jackson and Kronos's Curse]. Just so you know, I posted the two stories pretty much at the same time, but is you are interested in the sequel to [PJKC], please go to [Hunters vs Amazons] because the news is there since I typed that one out first. And to those who have never read mt other story, I hope you will like this fanfiction! Remember, no vulgarities in the reviews!

Full summary: The Titan War is over and both the Greek and Roman camps are celebrating, but not with each other, sadly. However, Gaia the Earth Goddess is already stirring, unknown to anyone, and she knows that the demigods would stand in her way of destroying the world. So she devised a plan to get them out of the way at least long enough for her plans to unfold. She finds the power of Chaos, Mistress of the Universe. Using the little power she stole from Chaos, she sends the demigods that were considered the most dangerous to her plans into an abyss, one different from Tartarus. She believes they are simply trapped inside the black vortex. But she was wrong, instead, the demigods, both Greek and Roman, were sent into a separate world, a parallel dimension, where the Titans rule the world in the Gods place, and the Gods are the one seeking destruction! And to make it worse, Percy's a girl?

Disclaimer: Disclaimers will not be repeated in individual stories so listen up, I do not own PJO/HoO. If I did, this would be on FictionPress, not that I have an account there…

Chapter 1: Gaia's Plan

The Titan War had ended and the demigods and gods, Roman and Greek alike, were celebrating at their respective camps. There was some mourning involved, for those who lost their lives fighting the Titan army, but the mood was mainly festive. But not deep in the underground abyss, deep in the world separated from the world of the Titans and Gods. Somewhere older and far more sinister, Gaia's lair.

She was already stirring, due to the mass fighting that occurred on her domain. On land. Kronos did not realize it, but before Percy Jackson, son of Poseidon, and Luke Castellan, son of Hermes, completely brought him down, his war had disrupted Gaia from her sleep even more than usual. And Gaia had seen what had transpired during the war, and was especially angered by the downfall of her sons, Kronos and Krios, who was downed by Jason Grace, son of Jupiter and praetor of the Twelfth Legion, Camp Jupiter. She had not fully awakened yet, she still needed much more time. She knew she could really take all the time she wanted, but she could not wait. It had been decades since she was forced back to her sleep by the daughter of Pluto, Hazel Levesque. She was ready to open the Doors of Death and chain Thanatos. But she knew she could not risk the demigods, especially Nico di Angelo, son of Hades and someone who spends a fair amount of time in the Underworld, to find out about it early.

But what could she do? As much as Gaia wanted to, she would be unable to prevent that from happening unless she could distract the demigods. She did not have the power to do so. If only she could somehow trap the demigods who threatened her rising, she could carry things out smoothly and easily. As she was still trapped in sleep, Gaia could not do it of her own power-she could barely even move on her own. All she could do was plan.

Then, an idea stuck her. She remembered her ancestor, Chaos, the Mistress of the Universe(A/N: Please check the wiki if you doubt this, but Chaos is a female deity and was the original Greek deity in legends.), had the power to bend reality and that power would probably be very useful. If Gaia had that kind of power in her hands, she would be able to send the demigods someplace where they would not be able to interfere. However, Gaia also realized that her plan had two flaws. One was that it would be extremely difficult to obtain even a minimal fraction Chaos's infinite power. Chaos had not shown herself to the world for several millennia, and thus her whereabouts were unknown. And two, Chaos was the primordial goddess of air, the opposite of Gaia's own sphere of control, which consisted of the earth. So exactly how was she going to get Chaos's power? It would be no easy task.

Gaia was now in a dilemma. If she could not trap the demigods, her plan might be jeopardized. She knew the only way to prevent them from interfering would be to secure them someplace else. And the only way she could do that without killing them was to trap them in some sort of 'special' place. After all, she still needed some of the demigods for her plan, such as Percy Jackson, Nico di Angelo, Jason Grace, Hazel Levesque and a few others. Finally, Gaia decided to try and find Chaos, take some of her power, and send the half-bloods into a separate dimension, at least until their service was required.

Weeks passed as Gaia searched for Chaos. She used every ounce of energy she could spare. She searched everywhere she thought of. Nothing. She had no leads on her ancestor, and she was running out of valuable time. She would soon have to open the Doors of Death, and would soon have to make the proper arrangements for her pawns. She was getting desperate. She knew that she could easily defeat the two camps herself if she was awake, but she was…paranoid, afraid that if they were too much of a hinderance, her plan may fall before it even had a chance to stand. She needed Chaos's power. She needed it very badly.

Then suddenly, she remembered something extremely important. Long ago, when the world was created, Chaos left some residual energy in some remote places on Earth. Gaia cursed in Ancient Greek, cursing herself for not remembering that simple yet essential fact. But now she could locate the remaining energy. She was confident that she would be able to find that energy-so long as it was on Earth, she would find it. But there were minor seeds of doubt in her mind. She could not track Chaos herself, even after searching for weeks, so how will searching for her energy be any different? And does that residual energy still exist? It could have easily faded through time. There was a risk involved in searching. She could waste precious time if the energy was already gone. But if it was not, and if she finds it, she could go through with her plans far more easily. Gaia figured she did not have much to lose. And so, a new search began for her. This time, it was not fruitless.

In the city of Athens in Greece, after another half a month of searching relentlessly, Gaia had discovered the ruins of a temple built in honor of Chaos. It was so old more than half of the building remains were nothing but pure white dust. From her lair, Gaia searched the ruins with as much of her own energy as she could. She had searched Greece for Chaos earlier, so she honestly did not expect anything would be found. But she checked anyway. Soon enough, she sensed unusual energy radiating from one particular part of the ruins. She rushed toward the energy and found what she had been searching for. When she found it, her sinister laugh of triumph shook the Earth itself.

Olympus had not yet realized Gaia was stirring. Hera had not yet been taken. The two camps had not yet stopped their normal lives to prepare for another war. No one knew that anything would even happen. Well, anything that was life-threatening at least, because a few things did happen, only without any relation to the Evil Earth Mother. Percy and Annabeth Chase, daughter of Athena, had gotten closer than just friends now. Grover Underwood, Percy's best friend and satyr, became a Lord of the Wild and a member of the Council of Cloven Elders. Nico became his father, Hades's, ambassador. Jason became praetor alongside Reyna, daughter of Bellona. Many things have turned out for the better after the whole war was over.

But now Gaia had enough power to do what she wished with the demigods. She decided not to waste the energy she found, and only send those who threaten her plans greatly into the abyss she had created. A separate place unlike the punishing Tartarus. She believed that they would be trapped in the centre of time and space within that abyss. When she needed them, she could easily remove them from there. A perfect plan, or so she thought. Gaia never expected just how differently Chaos's power would work.

Gaia opened the Doors of Death. Now no one would die unless she saw it necessary. Her son, the giant Alcyoneus, bane of Hades/Pluto, would guard Thanatos at Alaska for as long as she needed. Mother Earth would only have to wait for Nico di Angelo to pull his sister out of the Underworld. She would then make her move and her plans would go so much more smoothly. Soon enough, within days of her opening of the Doors, Nico found Hazel and both left the Underworld. Nico bought Hazel to Camp Jupiter and asked Reyna to take her in, but Gaia decided to do it before that meeting was even over. She released the amount of energy she needed, and the demigods did not realize what was heading their way.

So as Nico was talking to Reyna and Jason with Hazel by his side, all four of them felt the ground beneath them shaking. Then they felt intense pain in their heads, rushing at them like Grover on enchiladas' day.(A/N: Still don't know what those things are…) Before they could react and scream, the world turned dark for them.

Over at Camp Half-Blood, similar things were happening. Percy was just talking to Chiron, the centaur activities director of the camp, with Annabeth, about some personal matters, and that was when it happened for them. The same things occurred. The ground shook for the two demigods, but apparently Chiron felt nothing. The pain came swiftly, and soon everything went black. It was different for Chiron. He simply watched in horror as his two top students collapsed and dissolved into nothing. Of course, that set off the camp emergency alarms. Chiron rushed out of the Big house in a mad panic few have ever seen him in.

The two campers were not the only places from where the demigods disappeared. Somewhere in the wilderness, Thalia Grace, daughter of Zeus, vanished before Artemis, Goddess of the Hunt, and the Hunters' eyes. In North Vancouver, at Frank Zhang, son of Mars's, grandmother's house, Frank was minding his own business in his room, thinking about his mother, Emily Zhang, who had just gone to war in Afghanistan. Ground shaking and pain came and went as he too disappeared from his room. At the Wilderness School, where the satyr Gleeson Hedge was prancing around like a mad gym teacher with a cupcake obsession, two more demigods vanished from their classroom, causing a lot of screaming from their classmates. Leo Valdez and Piper McLean. With the two checked off, Gaia's list of 'Demigods out of the way' was complete. However, she did not know that they were not just floating around in empty space. They were sent somewhere that was too unbelievable even for gods.

Author's note:

Well there's your first chapter of this! Sorry I centered it on Gaia, but it was suitable. Remember to check out [Hunters vs Amazons] too! Merry Christmas!