Perhaps there's a powerful artifact that can only be activated by a father - daughter bond between Percy and Artemis. They are forced to work together to find and use this artifact to stop a great catastrophe. Along the way, they face many challenges. Percy has to deal with the fact that Artemis is a very different kind of 'daughter' compared to what he might expect, and Artemis has to come to terms with having a father figure for the first time in her existence.
One idea could be a quest where Percy and Artemis have to team up to rescue a group of demigods captured by a powerful new enemy. Maybe a Titan who has found a way to drain the powers of young demigods. Percy's skills in water manipulation and combat, combined with Artemis's archery and her connection to the moon, would make for an exciting adventure as they face various challenges along the way.
One plot idea could be Fem Percy Jackson joining Artemis' hunt. Since Percy has her own set of skills and powers, it would be interesting to see how she adapts to the life of a hunter. Maybe she could bring a new perspective to the group and help them in ways they haven't thought of before.
One interesting plot idea could be Percy having to team up with Artemis on a quest that involves an ancient artifact that has the power to disrupt the balance between the gods. Maybe it's an artifact that can control the tides in a way that endangers both land and sea. Another idea is a story where Artemis is somehow in danger and Percy has to use his skills and connection to the sea to save her while also dealing with her hunters who are initially suspicious of him. And a third plot could be about Percy and Artemis finding a new, unknown demigod who has powers that are a mix of the sea and the moon, and they have to figure out how to train this demigod and protect them from those who would misuse their powers.
One idea could be Percy having to protect Artemis from a new and powerful monster that has a special ability to track her. Another could be Percy and Artemis teaming up to retrieve a lost magical artifact that is important for the balance of the world. Maybe Percy has to enter Artemis's domain in the forest and face challenges there while protecting her.
One idea could be that the child has unique powers inherited from both Percy and Artemis. For example, the ability to control water like Percy and also have a strong connection with the moon and hunting like Artemis. Another plot could involve the child trying to find their place in the demigod world, being part of two very different lineages. They might face challenges from both sides, some who are suspicious of their mixed heritage.
Here's a more complex plot. In the fanfiction, Percy discovers that there's a prophecy related to the Hunters of Artemis that could change the balance of power between the gods. He's drawn into this mystery as the Hunters suspect he might be the key to either fulfilling or preventing the prophecy. Along the way, he forms an unexpected bond with one of the hunters, which causes some internal conflict among the group, as they have sworn off relationships with males. This would create a lot of drama and interesting character dynamics.
A plot could involve Percy accidentally stumbling into Artemis' territory. At first, Artemis is angry but then realizes Percy has information about a threat to her hunters. So they start an adventure to stop this threat. During the journey, they learn more about each other's worlds and develop a mutual respect. Or maybe there's a spell that makes Artemis lose her powers temporarily and Percy has to protect her while she regains them.
One idea could be that the daughter of Artemis has unique archery skills that she uses to protect Percy during a dangerous quest. Maybe she can communicate with animals in a special way, like her mother, which helps them gather information or escape from enemies.
A really interesting plot might be a story where Percy has to protect Artemis from a curse that is slowly draining her power. This could involve him going on a quest to find a cure, facing many challenges along the way, and developing a deeper understanding of Artemis. There could be some really cool moments where Percy uses his water - based powers in unique ways to help Artemis. Also, there could be some great character development as they interact more and more. This type of plot would also allow for exploration of the relationship between a male hero and a female goddess in the context of the Percy Jackson universe.
One idea could be that Percy discovers a new power related to chaos while on a quest with Artemis. This power could be the ability to manipulate time in small bursts, which helps them escape a dangerous trap set by an ancient monster.