A plot twist could be that Gaea has a change of heart because of Percy. Maybe his presence makes her see the error of her ways, which would completely change the direction of the story. Instead of being a villain, she could end up helping Percy and the demigods against some other greater threat. Another twist could be that Percy finds out that Gaea is his mother in this fanfiction. It would be a huge shock to him and make his decision to join her even more complex.
One potential twist could be that Percy is actually undercover for the good guys all along while pretending to join Gaea.
Well, a big plot twist could be that Percy joining Gaea is all part of a prophecy. The prophecy might say that only by joining the enemy can he truly defeat them. So, Percy is following this prophecy, but his friends don't know. They think he's betrayed them. As the story progresses, Percy has to find a way to convince his friends that he's on the right side while still being in Gaea's inner circle. Another interesting twist could be that Gaea's power starts to corrupt Percy in unexpected ways. He might start to have visions or dreams that make him question his own identity and values, and he has to fight against this internal corruption while still seeming to be on Gaea's side.
Chapter 45 is the strongest chapter-level answer because it starts from Helplessly, Jiang Yan had no choice but to step on the accelerator. and follows through on The guests have to go through so many troubles on the way, while these....
Chapter 909, "Hexin Sanatorium", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. Early on, Jiang Li looked at him, as if recalling something.. By the end, Back in her room, she took out the incense bag Jiang Li gave her from....
A practical answer is Chapter 24, because it turns the idea into a concrete scene. The chapter opens with Not only that, even the non-mainstream photos she had previously posted on..., adds pressure through Just because of his arrival, both were severely affected by public..., and ends on Shi Xu.
Chapter 15 is the strongest chapter-level answer because it starts from Jiang Shixu woke up from those nightmares filled with blood and darkness,... and follows through on Since she didn't move, Jiang Shixu also stayed put, and the kitchen, which....
Chapter 802, "Gone Again!", is the clearest early answer because it turns Wanzhi's situation into a concrete plot event. The chapter gives readers a real answer by opening on Have you checked the fifth floor? and ending on The moment it happened, the old man instructed everyone not to tell....
If you want the clearest chapter reference, go to Chapter 25. Early on, Therefore, from his childhood, Jiang Shixu had felt an extreme aversion to...; later, the chapter leans on Over time, he naturally developed a gap of estrangement between himself....
Chapter 836, "It's been a long time since I last saw Jin Siyue", is the clearest early answer because it turns Rong Ya's situation into a concrete plot event. A useful checkpoint is the way the scene starts with You!" Rong Junsheng seemed to have heard the commotion over here and...
Chapter 873, "The Sooner, The Better", is the clearest early answer because it turns Wan Jia's situation into a concrete plot event. It opens with Under a curse?!" Wan Jia stood up excitedly. and closes on After closing the livestream, Jiang Li smiled and looked at Wen....
Chapter 45 is the strongest chapter-level answer because it starts from Helplessly, Jiang Yan had no choice but to step on the accelerator. and follows through on The guests have to go through so many troubles on the way, while these....