Well, you could have a story where an eclipse is a portal to a different realm in the Percy Jackson universe. Percy accidentally stumbles through it during an eclipse and has to figure out how to get back. He might meet new characters there, like ancient gods or monsters that were exiled to that realm. And he has to use his wits and powers to survive and return home. This could also lead to a whole new arc in the fanfiction where the knowledge he gains from that realm helps him in future battles in his own world.
One idea could be Percy having to deal with an eclipse - related curse. Maybe during the eclipse, his powers go haywire and he has to find a way to control them before he endangers his friends. Another could be a new prophecy that is only revealed during the eclipse, sending Percy and his friends on a dangerous quest.
A cool plot for Percy Jackson Eclipse fanfiction could be that during the eclipse, all the demigods' memories get jumbled up. Percy wakes up not remembering who he is or his friends. His friends then have to help him regain his memories while also dealing with the chaos that the memory - loss has caused among all the demigods. There could be some internal struggles as well, like Percy having to trust his friends even though he doesn't remember them, and his friends having to deal with this new, somewhat lost Percy.
Chapter 939, "When Did the River Moon First Illuminate People? [Extra · River Moon Chapter]", is the clearest early answer because it turns Sister Li's situation into a concrete plot event. Early on, Using food to win over Shang Shuyue really works..
Chapter 34 is the strongest chapter-level answer because it starts from Seeing that the public sentiment wasn't quite right, Su Yinwan felt... and follows through on Now that Lili is misunderstood, they start to kick us while we're down."....
If you want the clearest chapter reference, go to Chapter 22. Early on, Hearing this, Su Yinwan looked at Shang Shaojing with a face full of...; later, the chapter leans on Shang, but it's not necessary; I haven't been wronged." After she spoke,....
Chapter 35 is the strongest chapter-level answer because it starts from Shining Transformation Trip's filming location was set on the distant... and follows through on Brother is really hardworking, actually arriving at the same time as the....
A practical answer is Chapter 79, because it turns the idea into a concrete scene. The chapter opens with Jiang Li leisurely said, "I bought this weeding machine, and according to..., adds pressure through Many had even spontaneously formed a fan group for Jiang Yan, promoting..., and ends on.
If you want the clearest chapter reference, go to Chapter 26. Early on, Shen Lan was bent over processing a large stack of press briefs on her...; later, the chapter leans on She was nearly forty years old, but because she took good care of herself....
Chapter 78 is the strongest chapter-level answer because it starts from He Yun, too, tidied up and walked over to rest in the shade of a tree. and follows through on [HAHAHA, is it just me or does Movie Emperor He seem to be showing off a....
If you want the clearest chapter reference, go to Chapter 58. Early on, Facing Jiang Yan's triple barrage of questions, Jiang Li's only response...; later, the chapter leans on After a long while, she yawned indifferently and said, "I didn't pick up....
Chapter 11 is the strongest chapter-level answer because it starts from After a meeting, Shang Shaojing pinched the bridge of his nose, tired, and... and follows through on Miss Qin, please accompany us to the police station to explain this....
If you want the clearest chapter reference, go to Chapter 26. Early on, Shen Lan was bent over processing a large stack of press briefs on her...; later, the chapter leans on She was nearly forty years old, but because she took good care of herself....