The plot could start with Naruto being suddenly snatched by the Kyuubi during a mission. The Kyuubi might take Naruto to a secret lair. It could be that the Kyuubi is lonely and has always been misunderstood. By kidnapping Naruto, it hopes to make him understand its true nature. Maybe the Kyuubi wants Naruto to see the memories of the past, the times before it was sealed inside him. This could open up a whole new world for Naruto, and he might start to question the history and the way the village has treated the Kyuubi. However, Naruto would also be in danger as the Kyuubi's power is still very much a threat, and he would have to figure out a way to either escape or come to some sort of truce with the Kyuubi.
One possible plotline could be that Naruto is kidnapped by Kyuubi to gain some sort of power or knowledge from him. Maybe the Kyuubi believes Naruto has a secret that can help it break free from its current state. Another could be that Naruto is kidnapped as a way to get back at the Hidden Leaf Village, and the Kyuubi uses Naruto as a bargaining chip. It could also be that there is some external force that makes the Kyuubi kidnap Naruto, like a dark wizard or something similar that has control over the Kyuubi.
One possible plotline could be that Hinata is under some sort of mind - control. Maybe an enemy uses a jutsu on her that makes her see Naruto as a threat to the village in a false way. So, she kidnaps Naruto to stop him from doing something she believes is harmful. But as the story progresses, Naruto tries to break through to her real self and free her from the mind - control.
One possible plotline could be Naruto growing up with a sense of deep abandonment and having to face the world alone. This could lead to him having a much more cynical view of life. He might struggle more with controlling the Kyuubi's power as he has no guidance from Kushina. Another aspect could be his relationships with other characters like Iruka or Sasuke being different. Without Kushina's love, he may be more desperate for any form of connection.
One possible plotline could be that Annabeth is kidnapped by a group of mythical creatures who mistake her for someone else. They take her to their lair deep in the forest. Her friends then have to embark on a dangerous journey to find her, facing various challenges along the way. Another could be that a powerful enemy from her past kidnaps her to use her knowledge of architecture for some evil plan, like finding a hidden powerful artifact.
One possible plotline could be that Osomatsu is kidnapped by a rival gang who wants to use him as a bargaining chip against his brothers. His brothers then have to go on a wild adventure to rescue him, facing various challenges along the way. Another plotline might be that he is kidnapped by a crazy fan who is obsessed with him and wants to keep him all to herself. Osomatsu has to figure out how to escape while dealing with the fan's erratic behavior. And a third plotline could be that he is kidnapped by an evil entity from another dimension who mistakes him for someone with special powers.
In a fanfiction where Carl Grimes is kidnapped, he could be taken by a group of survivors who are desperate for supplies. They see Carl as a valuable asset to trade with his group. Carl, while kidnapped, tries to convince them that working together would be more beneficial. He might share his knowledge of survival skills and how his group has managed to build a community, hoping to change their minds and gain his freedom.
One possible plotline could be that Darcy is kidnapped by a group who want to use her knowledge of a certain scientific discovery she was involved in. They might hold her in an abandoned warehouse and try to force her to reveal the details. Another could be that she's kidnapped by an alien species who mistake her for someone more important in the scientific community on Earth. They take her to their ship and she has to find a way to escape while also learning about their motives.
Another plot could be that a time - traveling wizard from the future kidnaps them to prevent some future catastrophe that they unknowingly cause. James and Lily then have to figure out how to get back to their own time while also dealing with the kidnapper's motives and the strange future world they find themselves in.
One possible plotline could be that Zoro is kidnapped by an enemy from his past who wants revenge. Maybe a pirate he defeated before has come back with a stronger crew and takes Zoro to lure the rest of the Straw Hats. Another could be that he's kidnapped by a secret organization that wants to use his strength for their own purposes.
One possible plotline could be that Naruto is lured into a trap by the Akatsuki. They use his overconfidence against him. Maybe they pretend to have a hostage that Naruto wants to save, and when he arrives, they overpower him with their combined jutsu. Another could be that they manage to find a way to nullify his Nine - Tails chakra, leaving him vulnerable to their attacks.
One possible plotline could be that Naruto's wings make him an outcast in the village at first. People are scared or jealous of his unique feature. But as he grows, he learns to use his wings in combat, perhaps in a new style of ninja fighting that combines aerial maneuvers. He could also use his wings to reach places quickly during missions, giving him an edge.