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.
In some fanfictions, Darcy might be kidnapped by a time - traveling villain who wants to change the course of history. Since Darcy has been involved in some significant events, the villain thinks that by getting rid of her or using her, they can alter the future to their advantage. She has to then figure out how to break free and stop the villain from messing with time.
Perhaps Darcy is kidnapped by a rival scientist who is jealous of her achievements. This rival locks her away in a secret laboratory and tries to make it seem like Darcy has disappeared on her own. Darcy then has to outwit this scientist and use her wits to get a message out to her friends for rescue. Or it could be that she's kidnapped by a cult that believes she has some sort of special power because of her association with certain scientific events, and they want to use her in their rituals.
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.
It could be a disgruntled former colleague. Maybe they felt overshadowed by Darcy in their work and decided to kidnap her out of envy. They might think that by getting her out of the picture, they can take all the credit for their shared projects.
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.
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.
A lot of 'Darcy Lewis hurt' fanfictions explore her vulnerability. For example, some might have her get hurt in a fight against villains. These stories often delve into her inner strength and how she overcomes the hurt, which can be really inspiring for readers.
Perhaps Drake is kidnapped because he has uncovered a dark secret in Ripper Street. The kidnappers could be trying to silence him. His captors might hold him in an abandoned building, and he has to use his wits to try and escape while his colleagues search the seedy underbelly of the street for him. This could involve a lot of tense moments as the kidnappers threaten him and his friends get closer to finding him.
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 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 plot idea could be that Darcy discovers she's pregnant in the middle of some scientific research chaos. Maybe she has to deal with the secrecy of her pregnancy while still trying to contribute to the project she's involved in. Another idea is that the father of the baby is a mysterious figure, and she has to figure out how to tell him and what their future holds. And a third idea could be that her pregnancy causes a stir in the scientific community she's part of, with some being supportive and others doubting her ability to continue her work.