Perhaps the lost glasses are not ordinary glasses at all. They could be from a different world or dimension. Felicity's kidnapping might be part of a larger plot to retrieve the glasses for some dark purpose. The fanfiction could explore how Felicity uses her wits and skills to outsmart the kidnappers and either keep the glasses safe or use them to her advantage. It could also have elements of mystery and suspense as the true nature of the glasses is gradually revealed.
In this kind of fanfiction, perhaps Felicity is kidnapped and her glasses are missing as part of some grand plot. Maybe it's a mystery where her friends have to find her and also figure out what happened to her glasses. It could be that the glasses hold some important clue or power in the story's universe.
Perhaps it's a jealous rival. Maybe in the world of this fanfiction, there's some sort of competition, like for a job or a love interest. And this rival decided to kidnap Felicity to get her out of the way.
Another possibility is that a mysterious stranger comes to her rescue. This stranger might have been secretly following her kidnapper. He or she could fight off the kidnapper and then take Felicity to a safe place. And then they help her find a new pair of glasses.
Perhaps Felicity has a hidden power that is only activated when she has her glasses. Without them, she has to find an alternative way to fight back against her kidnappers. This could lead to her developing new skills or alliances within the story.
It could be the kidnapper. They might pick up the glasses as a way to taunt Felicity, or perhaps they keep them as a sort of trophy. It would add to the psychological warfare between them.
Well, it could be that the loss of her glasses is just a random event in the chaos of the kidnapping. However, in fanfiction, it might also be used to create a moment of humor. Maybe when her glasses fall off, she makes some comical remarks about not being able to see the face of her kidnapper clearly. Or perhaps it's a way to show her clumsiness in a high - stress situation, which could be endearing to some readers.
The lost glasses could be a MacGuffin in this fanfiction. Felicity being kidnapped might be related to her connection to the glasses. Maybe she was the last person seen with them. It could lead to a story where she has to find the glasses while being held captive to bargain for her freedom.