One idea could be Percy having to go on a quest that involves both Athena and Artemis. Maybe he has to retrieve an ancient artifact that is sacred to both goddesses. Another could be a story where Percy gets caught in the middle of a feud between Athena and Artemis over a new demigod's loyalty. For example, the new demigod shows great skills in both wisdom (Athena's domain) and hunting (Artemis's domain), and the two goddesses start to compete for the demigod's allegiance, with Percy trying to keep the peace.
There could be a story where Artemis is missing, and Athena believes Percy has the skills to find her. Percy embarks on a journey, following the clues that Athena provides. Along the journey, he learns more about the relationship between the two goddesses. He discovers that their differences, which often seem to put them at odds, are actually what makes their combined power so important. When he finally finds Artemis, they all have to team up to defeat a common enemy that was trying to take advantage of Artemis's absence to disrupt the natural order.
One plot idea could be that Percy finds himself in a situation where he has to seek the wisdom of Athena and the protection of Artemis while being mysteriously linked to a lemon. Maybe the lemon is a magical object that only he can unlock its power, and Athena helps him figure out how to do it while Artemis guards him from those who would steal it.
Maybe a fanfiction where there's a competition in Olympus related to lemons. Artemis and Athena both enter, but for different reasons. Artemis is intrigued by the idea of a new kind of hunt (hunting for the best lemon - related item perhaps), and Athena sees it as a mental challenge. As they compete, they learn more about each other's perspectives and form an unexpected bond.
One idea could be that Percy has to seek Athena's wisdom to solve a complex mystery in the mortal world that is somehow related to the gods' ancient secrets. Maybe it involves a powerful artifact that was lost long ago and only Athena's knowledge can lead Percy to it.
Another plot could involve Percy getting a vision from Athena about a future threat to the demigod world. But the vision is so cryptic that he has to work closely with Athena to decipher it. Along the way, they build an unexpected bond, different from his usual relationships with other gods. Maybe Percy starts to see Athena not just as a powerful deity but as a mentor figure, and Athena starts to respect Percy's tenacity more than she expected.
One idea could be Percy going on a quest to find a lost artifact of Athena that has the power to restore balance in the world of the gods. Another could be Percy having to face off against a powerful enemy who is specifically targeting him because of his relation to Athena. Maybe he discovers some long - lost siblings also sired by Athena during his adventures.
Perhaps Athena's love for Percy causes a rift between her and her daughter Annabeth. This could lead to a complex story of family drama, loyalty, and love. Or, in some fanfictions, there could be a plot where Athena's love is a curse placed on her by an enemy, and Percy has to find a way to break the curse, all while they both struggle with their new - found emotions.
One idea could be that the child has special powers inherited from both Percy and Artemis. For example, they might have the ability to control water like Percy and also have a connection to the moon or be an excellent archer like Artemis. Another plot could involve the child trying to find their place in a world where demigods are already a complex group. They might struggle with the expectations of both their parents' legacies.
Maybe there could be a situation where Percy is injured and Artemis has to take care of him. In the process, she starts to develop feelings that she doesn't quite understand at first. Percy, on the other hand, is in awe of her strength and beauty even more up close, and this could be the start of their love story.
Maybe in the fanfiction, there's a prophecy that only Percy and Artemis together can stop a great evil. They are reluctant at first to work together as their relationship has always been more of acquaintance. But as they train and plan, they start to share personal stories and experiences. Their bond deepens, and it turns into a romantic relationship as they realize how much they admire and respect each other.
One idea could be Percy joining the Hunters of Artemis on a special quest. Maybe they are seeking a powerful magical artifact that has been lost for centuries. Percy's unique skills as a demigod could be really useful in this situation.