In this fanfiction, it could be that Artemis is in a situation where she is about to be killed or lose her powers forever. Percy, being the selfless hero he is, takes on a deadly task to prevent that from happening. Maybe it involves facing an ancient and malevolent god who has a vendetta against Artemis, and Percy uses his unique abilities and the element of surprise to try and stop this god, but at the cost of his own life.
It could be a powerful Titan who has escaped from Tartarus and blames Artemis for something in the past. So he's out to get her, and Percy has to stop him at all costs, even if it means his death.
One possible plot could be Percy having to defend Artemis from a new and powerful enemy. Maybe a primordial being has awakened and is targeting Artemis. Percy, with his skills and the help of his friends, must fight this enemy. He could also have to deal with the politics among the gods as he tries to protect Artemis, since some gods might not be so happy about his interference.
Well, it could involve Percy being tasked with protecting Artemis in a way that goes against his normal alliances. Maybe some dark force is after Artemis and Percy has to use his skills in a new and unexpected way.
One possible plot could be that the son of Artemis discovers a threat to the demigod world that is related to his mother's domain. He then seeks out Percy for help because of Percy's reputation. Together, they embark on a journey to find a magical artifact that can stop the threat.
In a 'Percy Jackson adopted by Artemis' fanfiction, perhaps Percy is exiled from Camp Half - Blood due to false accusations. Artemis, who has always been intrigued by Percy's courage, takes him in. With Artemis as his new guardian, Percy gets involved in the Hunters' battles against ancient monsters that threaten the world. He also has to deal with the jealousy of some of the other Hunters who are not happy about a male being in their midst.
A possible plot in such a fanfic could be Percy trying to bring Sally back from the dead. He could go on a dangerous and forbidden quest, defying the gods and the natural order. This would put him at odds with many, but his love for his mother is so strong. He might encounter dark magic or make deals with shadowy figures in his desperation, all while his friends are worried about him losing himself completely in this quest.
It could start with Artemis getting into a situation where she's in a vulnerable position. Maybe she's been lured into a place where her powers are diminished. Percy, being a friend and an ally, rushes to her aid. Along the way, he has to fight through hordes of lesser monsters, which takes a toll on him. When he finally reaches Artemis, they are confronted by a really powerful adversary. Percy realizes that the only way to save Artemis is to take the full brunt of the enemy's attack himself. So he does, and that's how he dies.
Well, it could be about Percy having to deal with the conflict of being the son of two such different deities. Maybe he has powers from both Orion and Artemis. For example, he could have Orion's hunting skills combined with Artemis's connection to the moon. He might struggle to fit in with the normal demigods as his origin is so unique.
The plot could involve the son of Artemis facing abuse from other demigods who are jealous of his unique parentage. He might struggle to find his place in the Camp Half - Blood, constantly facing discrimination and harm. Then, perhaps Percy Jackson could come to his aid and together they try to expose the bullies and change the situation at the camp.
She might be on a quest to retrieve a lost artifact of Artemis. This could involve traveling to different mythological locations, facing monsters along the way. Her skills as a daughter of Artemis, like her archery and tracking abilities, would be crucial in this journey.