Well, perhaps a plotline where Percy and Annabeth discover some long - lost secrets or powers within Tartarus. Maybe they find an ancient artifact that has the potential to either help them escape or change the fate of the world above. And of course, there could be a plotline centered around their relationship growing stronger as they rely on each other to survive the perils of Tartarus.
One interesting plotline could be their struggle against the various monsters in Tartarus. For example, facing off against the giants or other terrifying creatures that lurk there. Another could be their search for a way out while dealing with the psychological toll of being in such a dark and desolate place.
One popular type of fanfic could be about Percy and Annabeth's journey through Tartarus. It might focus on their struggles, like how they face the various terrifying monsters there. Maybe they use their unique powers and the bond between them to survive. For example, Percy's control over water could be crucial in crossing some of the dangerous rivers in Tartarus, while Annabeth's wisdom helps them make smart decisions when choosing paths in that dark and chaotic place.
One interesting plotline could be Percy's struggle against the various monsters in Tartarus. He might have to use his wits and powers in new ways to survive. Another could be his journey to find a way out, perhaps making unexpected alliances with other beings trapped there.
One interesting scenario could be Percy and Annabeth finding a hidden, powerful weapon in Tartarus that gives them an edge against the monsters there. Maybe it's a sword that can cut through the very fabric of Tartarus's darkness.
One more plot idea could be that Percy and Annabeth are somehow affected by the dark magic of Tartarus. It changes them in some way, either physically or mentally. They then have to deal with these changes while still trying to escape. This could lead to some really intense internal and external conflicts as they struggle to stay true to themselves and also find a way out of Tartarus.
Another plotline could be that Annabeth is in a dangerous place like a cursed island. Percy has to fight his way through various mythological creatures and traps to reach her. Along the way, he discovers new aspects of his own powers as he is driven by his love for Annabeth and his determination to save her.
One good 'Percy and Annabeth Tartarus fanfic' is 'Into the Depths'. It really captures the struggle and bond between Percy and Annabeth in Tartarus. The author does a great job of describing the terrifying environment.
Perhaps there's a plotline where Percy discovers new and dark powers within Tartarus that he has to learn to control. This could lead to him having to make difficult choices about whether to use these powers for good or risk being consumed by them. He may also encounter other fallen or corrupted beings that either try to help or hinder him on his journey.
They could discover a lost civilization in Tartarus. This civilization might have a way to manipulate the very fabric of Tartarus itself. Percy and Annabeth would then have to learn the ways of this civilization in order to use it to their advantage. Maybe they have to earn the trust of the civilization's leaders by helping them with their own internal problems first.
One possible plotline could be Percy's struggle for survival in Tartarus. He might face various terrifying monsters and have to use his wits and powers to stay alive. Another could be his journey of self - discovery in that dark place, realizing new aspects of his abilities or his past. Maybe he also tries to find a way to escape Tartarus while also dealing with the psychological toll of being in such a desolate and dangerous realm.
Percy might develop more of a steely determination. In Tartarus, he has to face extreme danger, which could make him even more resolute in protecting Annabeth and getting out. Annabeth, on the other hand, could become more resourceful. She'd have to use her wits in this strange and deadly place.