One idea could be that the next - generation charmed ones accidentally travel back to a key moment in their parents' time as charmed ones and have to make sure not to disrupt the past too much while also learning important lessons about their own powers. For example, they might witness a difficult battle their parents faced and gain new insights into a family spell.
Another plot could involve time travel to an era where magic was first discovered. The next - generation charmed ones could get involved in the origin story of magic in their world. They might have to protect the first magic users from an evil force that wants to stop magic from ever developing, which would change the entire course of their own present and future.
One idea could be that the next - generation characters travel back to the time of the first wizarding war to prevent a certain event that had a long - lasting negative impact on their families. For example, stopping the death of a beloved ancestor.
One idea could be that the next - generation Avengers accidentally travel back in time and interfere with a key event in the original Avengers' history. This causes a ripple effect that changes the present in unexpected ways. For example, they might prevent Tony Stark from creating the first Iron Man suit, leading to a world where technology has developed differently. They then have to figure out how to fix the timeline while also dealing with the different threats in this new reality.
One idea could be that the next - generation characters travel back to the time of the first wizarding war. They could accidentally change some small events, which then have big consequences on their present time. For example, they might prevent a certain spell from being cast that was crucial in the defeat of a dark wizard, and now they have to figure out how to fix it in their own time.
The children of the original charmed ones would be obvious main characters. They could inherit some of their parents' powers and personalities. For example, if Piper had a daughter, she might have some power over freezing time like her mother, but with her own unique twist.
Another plot could revolve around a time - travel aspect in the Twilight Next Generation fanfiction. A young character accidentally travels back in time to when their parents first met and starts to interfere. This could lead to all sorts of changes in the timeline and force them to find a way to fix it before they cease to exist in their current form.
One idea could be the next generation facing a new, more powerful enemy that combines the powers of all the previous villains. They'd have to learn from their parents' stories and develop new skills to defeat it.
A plot idea could be that the next generation of Miraculous holders has to team up with some of the old villains' descendants who are now on their side. They have to overcome the prejudice from the public who don't trust them. Together, they work to stop a new evil that is threatening to destroy the balance between the Miraculous powers and the normal world.
One idea could be about a new type of Pokemon that emerges in the next generation. Maybe it's a fusion of two existing types due to some strange environmental phenomenon. Another could be a story where the main character is a descendant of a famous Pokemon trainer from the previous generations and has to live up to their legacy while facing new challenges in the Pokemon world.
Another plot could involve the next - generation Avengers having to prove themselves to the world. The public is skeptical of them at first, thinking they can't live up to their parents' legacies. So they take on a mission to save a major city from a powerful alien invasion, and in the process, they gain the public's trust.
Another plot could revolve around the relationships between the children of the original RWBY characters. For example, if Ruby's daughter has a different view on hunting Grimm compared to her mother. It could lead to internal conflicts within the new team and also show how the world has changed since the first generation's time. There could be political aspects too, like new laws regarding Huntsmen and Huntresses that they have to navigate.