She could use it to tie up the kidnapper if she gets the chance. For example, when the kidnapper is distracted, she could quickly loop the hair tie around his hands and tighten it, restricting his movement.
The fact that her hair is in a bun might also play a role. It could be a cultural or traditional style in the fictional world she belongs to. When she's kidnapped, her captors might be disrespectful of this style, which angers her and gives her the motivation to resist. The bun could also be used practically during her captivity. For example, she might hide small objects in it to help her escape, like a lock pick or a small note.
The hair tie on her wrist could be a symbol of her past normalcy. Maybe it was something she put on in a hurry before being kidnapped, like a reminder of her everyday routine. It could also potentially be used as a weapon or a tool for escape if she manages to get it off her wrist.
Well, first, establish the character who has the hair tie on their wrist. This character could be a very popular or important person in the fanfiction world. The kidnapper might target them because of their status. During the kidnapping, the hair tie could get damaged, which adds to the tension. The character then has to find a way to repair it or use it in its damaged state to escape. For instance, they could use a broken part of the hair tie to cut through ropes if it's made of a strong material. The hair tie can also be a connection to other characters. For example, another character might see the hair tie on the news when the kidnapping is reported and recognize it as belonging to the kidnapped character, which then sets off a chain of events to rescue them.
The story could start with the girl going about her normal day, the hair tie casually on her wrist. Then suddenly, she's grabbed and taken away. The hair tie might play a role in her escape plan. For example, she could use it to leave a trail or as a tool to pick a lock if it's long enough and strong enough.
It can be a clue. For instance, the hero in the fanfiction might notice the hair tie on the wrist of a suspect and start to suspect that person of being involved in the kidnapping. It's a simple but effective way to introduce an element of mystery and investigation into the story.
A disgruntled ex - friend could be the kidnapper. Maybe there was a falling - out between the two characters, and the ex - friend wants to get back at the owner of the hair tie. They think that by taking this precious item, they can cause emotional pain.
Perhaps the girl was kidnapped because she was wearing the hair tie in a certain way that is significant to a cult or a secret society. They believe she is a chosen one or something similar. As she's held captive, she learns about their strange beliefs related to the hair tie and tries to use that knowledge to turn the situation around and free herself.
In the fanfiction, her hair tie could be enchanted. When she's kidnapped, she discovers that she can use it to send out a distress signal only visible to those she trusts. Her bun could also hold a secret. There could be a hidden tattoo on the back of her neck that is only visible when her hair is in a bun, and this tattoo is the key to a great treasure. The kidnappers don't know this yet, but they will soon find out as the story unfolds.
It could be a key element in an emotional sense. If the mother is in distress, she might hold onto the hair tie as a way to keep her connection with her family. This can be a very powerful image in the fanfiction, and it could also inspire the people trying to rescue her. They see how much she loves her family through this simple hair tie, and it makes them more determined to save her. The hair tie can also be a symbol of hope throughout the story.
If it's a hair tie given to her by a friend, it could strengthen their bond. For instance, if it was from Angela, it would be a symbol of their friendship. Whenever Bella looks at it, she's reminded of their good times together, and it might make her more likely to reach out to Angela when she's having a problem, thus deepening their relationship.