One possible plotline could be that Lan is kidnapped by a group of rogue NetNavis who want to use his unique connection to MegaMan for their own evil purposes. They might try to force Lan to give up access codes or secrets about MegaMan's abilities.
Perhaps in the fanfiction, Lan is kidnapped by a mysterious organization that believes he has some sort of key or power within him that can unlock a powerful digital weapon. So they take him to their secret lair to try and extract this power from him. And MegaMan has to fight his way through various security systems and enemies to rescue Lan.
It could be that Lan is kidnapped by a jealous rival who wants to prove himself better. This rival might think that by kidnapping Lan, he can disrupt the bond between Lan and MegaMan and show that he can be a better operator. MegaMan then has to not only rescue Lan but also prove that their bond is unbreakable.
It could be a new villain created specifically for the fanfiction. Maybe a hacker who has a grudge against Lan's family or MegaMan's creators and thinks kidnapping Lan is the best way to get revenge.
One possible plotline could be that Stiles' friends immediately start a search. They might follow clues like strange footprints or a mysterious note left behind. Another could be that Stiles manages to outwit his kidnappers in some way while being held captive, perhaps by tricking them into revealing their weaknesses. Maybe the kidnappers are after something Stiles knows, like a secret about the supernatural world in the fanfiction's setting.
One possible plotline could be that Yami is kidnapped by a rival group who wants to use his special powers for their own evil deeds. His friends then embark on a dangerous mission to rescue him. Another could be that Yami is kidnapped as part of a ransom plot against someone he is close to, and they have to figure out how to meet the kidnappers' demands without sacrificing too much.
Well, it could start with Mycroft being lured into a trap and kidnapped. The kidnappers might be from a different dimension or have some sort of supernatural power. As the fanfiction progresses, Mycroft could use his wits to outsmart the kidnappers even while in captivity. There could be a lot of mind games and tense moments as he tries to escape or signal for help.
Perhaps in this 'imprijt kidnapped fanfiction', the kidnapped person is a key figure in a grander scheme. Imprijt kidnaps them to use as a bargaining chip against their friends or allies. The friends then embark on a rescue mission filled with various challenges and unexpected twists.
One possible plotline could be that Naruko is kidnapped by a powerful enemy who wants to use her as a bargaining chip against her friends or family. Another could be that she is kidnapped by a mysterious organization for some sort of experiment. Maybe she's kidnapped by someone who has a personal vendetta against her and plans to make her suffer.
One possible plotline could be that Keith is kidnapped by an enemy force. His friends then embark on a dangerous rescue mission, facing various challenges along the way. Maybe they have to infiltrate a heavily guarded enemy base to find and free him.
One possible plotline could be that Megaman and Roll have been through a difficult battle together. In the aftermath, with the adrenaline still high and a newfound appreciation for each other, they share a tender kiss. It could be a moment of realization for both of them about their deeper feelings.
One possible plotline could be that a deranged fan kidnaps the Beatles in an attempt to force them to play a private concert just for them. Another could be that a rival music group arranges the kidnapping to try and stop the Beatles' rise to stardom.
One possible plotline could be that Twilight Sparkle is kidnapped by a powerful dark magic user who wants to steal her knowledge of magic. Her friends then embark on a quest to rescue her, facing various challenges along the way. Another could be that she is kidnapped by an unknown force from another dimension for some sort of experiment. Her friends have to figure out how to cross dimensions to save her. A third plotline might be that a group of villains kidnap Twilight Sparkle to use her as a bargaining chip against Equestria, and her friends must find a way to outwit the villains and get her back safely.