Here's a plot. Percy and his cousins are invited to a special tournament among demigods from all over the world. But it turns out to be a trap set by an evil force that wants to use their combined powers for its own dark purposes. As they fight to escape, they learn more about their individual strengths and how to work together as a family. They also meet some interesting new characters from different mythologies during their struggle, and these new allies help them in unexpected ways to defeat the evil force and save the day.
Perhaps they go on a quest to find a lost artifact that has the power to save their mother from a mysterious illness. Along the way, they face various challenges and learn more about their family's past. They might also encounter other demigods who either help or hinder them in their search.
Perhaps Sally starts a support group for the parents of demigods. This could lead to some interesting interactions and new friendships. Percy could be involved in helping her set it up and deal with the various challenges that come with it, like keeping it a secret from the mortal world and protecting it from monsters.
One idea could be Percy having to go on a quest specifically for a goddess who has lost her powers. He has to travel to different realms and face new monsters to retrieve a magical item that can restore her. Another could be Percy getting caught in a love triangle between two goddesses, which causes chaos among the gods as they take sides.
One plot twist could be that they discover they are cousins much later in their respective adventures. For example, Percy might be on a quest in the Underworld and find out some long - hidden family secret that links him to Harry. Another could be that a seemingly friendly character turns out to be the one trying to keep them apart because their combined power is a threat to their evil plans.
One plot idea could be that Lemon has a special power that no one else in the demigod world has, and Percy has to protect her from the gods who want to use or destroy her because of it.
Well, a great plot could involve Percy and his father having to face a new and powerful enemy that is specifically targeting them because of their relationship. This could lead to them having to rely on each other's strengths. For example, Percy's father could use his powers over the sea to help Percy in a fight in a way that Percy has never experienced before. And as they go through this adventure, they could also have heart - to - heart conversations about family, duty, and what it means to be a hero.
One idea could be that his little sister discovers a new, hidden power within herself while on a quest with Percy. Maybe she can communicate with mythical creatures in a unique way that helps them solve a mystery.
One idea could be that they discover their family connection during a magical crisis. Maybe a dark force is threatening both the wizarding world and the world of the Greek gods, and their combined powers as cousins help in the fight. For example, Harry's knowledge of complex spells and Percy's control over water could be used in creative ways to defeat the enemy.
One plot idea could be Percy having to team up with Hera to rescue a group of demigods who have been captured by an ancient monster. Hera, despite her usual aloofness, realizes she needs Percy's unique skills.
One idea could be Percy having to go on a special quest for a particular goddess that involves retrieving a lost artifact. Maybe it's an ancient weapon that was stolen by a powerful monster. Another could be Percy getting caught in the middle of a feud between two goddesses and having to find a way to make peace. He could use his unique skills and the loyalty of his friends to negotiate a truce.