One possible storyline could be that they are kidnapped by a criminal organization that wants to use their intelligence for some evil plan. For example, they might be forced to solve complex puzzles or decrypt secret codes. Another storyline could involve a rival thief or detective who kidnaps them to prove their superiority. They could be held in an elaborate, hidden location and have to use their wits to escape.
A possible story could be that they are kidnapped as part of a larger conspiracy involving a powerful figure. This figure may see them as threats or as useful tools. The two of them could then team up inside the captivity, using their unique skills and knowledge of each other's methods to not only escape but also expose the conspiracy.
Perhaps they are kidnapped by a deranged fan who idolizes their skills. This person might be trying to create a situation where they can prove themselves to Kaito and Shinichi. In this case, the kidnapper could set up various challenges related to their areas of expertise, like heists for Kaito and crime - solving for Shinichi.
One possible plot twist could be that the kidnapper is actually someone they both know in disguise. Maybe it's a rival detective or magician who wants to prove they are better. Another could be that the place they are kidnapped to has some sort of hidden treasure or secret that the kidnapper is forcing them to find.
In such fanfiction, Shinichi is often depicted as still having his sharp detective mind. He's intelligent, observant, and tenacious in solving problems. Kaito, on the other hand, is shown as his flamboyant self, with his amazing skills in magic and disguise. He's also quite charming. Both of them might have a bit of a competitive streak towards each other, which adds to the tension and interest in the story.
A Bulma kidnapped fanfiction could involve her being kidnapped by an evil wizard who wants to use her intelligence to solve a complex magical riddle. The Z - fighters would then have to team up with some magic - using allies to rescue her. Another idea is that a group of intergalactic pirates kidnap her for ransom. They think the Z - fighters will pay a huge amount to get her back. And yet another possibility is that a mad scientist from a parallel universe kidnaps Bulma to force her to collaborate on a dangerous experiment.
It could be a secret society that has been observing their actions and sees them as a threat to their hidden agendas. This society might have members with special skills and resources to carry out the kidnapping.
One possible storyline could be that a rival team kidnaps Lillie to use her knowledge of the Aether Foundation for their own evil plans. Another could be that a powerful and mysterious Pokemon trainer, jealous of Lillie's bond with certain Pokemon, takes her. Or perhaps an ancient and long - forgotten evil entity returns and targets Lillie for reasons related to her unique connection to the Pokemon world.
One possible storyline could be that an evil organization kidnaps Captain America to extract his super - soldier serum secrets. They might hold him in a high - tech, hidden facility and try various methods to break him. Another could be that a powerful, rogue supervillain with a personal vendetta against Captain America kidnaps him to prove his superiority. The Avengers then have to race against time to find him, facing many obstacles along the way.
One possible storyline could be that Billy Batson is kidnapped by an evil organization that wants to figure out the secret of his transformation into Shazam. They might try to run all sorts of tests on him in a secret lair. Another could be that a supervillain who has a vendetta against Shazam kidnaps Billy to draw Shazam out. They could hold Billy hostage and demand that Shazam gives up his powers or something similar.
It could be a criminal mastermind who sees Shinichi as a threat to his illegal activities and Kaito as someone who can be used as leverage. Maybe a powerful underworld figure who has been on Shinichi's radar for a long time and decides to take action by kidnapping them both.
One possible storyline could be that Daphne is kidnapped by a vengeful villain from a past mystery they solved. The gang then has to retrace their steps to figure out who it is. Maybe they find some old clues that lead them to an abandoned mansion where Daphne is being held captive.
Well, a possible plotline is that Shinichi discovers Kaito's true identity before Kaito intends him to. This could lead to a series of events where Shinichi has to decide whether to expose Kaito or help him use his skills for good. Or perhaps there's a plotline where they both get caught in a time - travel situation and have to work together to get back to their own time while also dealing with the changes in the timeline. Another idea is that they enter a contest of wits and skills, which ends up making them respect each other more in the end.