She may also try to find a way to turn the situation around without giving in to the blackmailer's demands. Hermione is resourceful, so she might seek help from her friends in a very discreet way. She could use magic in creative ways to protect herself and the secret that the blackmailer is using against her. For instance, she could use a spell to make the evidence the blackmailer has useless.
In many fanfictions, Hermione's reaction is also influenced by her loyalty to her friends and the wizarding world. If the blackmail involves something that could harm them, she would be even more determined to fight back. She might sacrifice her own reputation or safety to protect those she cares about. For example, if the blackmailer threatens to expose a secret that would get Harry expelled, Hermione would go to great lengths to stop that from happening.
Hermione usually reacts with a mix of anger and determination. She's not the type to be easily pushed around. So, she might start by trying to figure out who the blackmailer is and what their motives are. For example, she could use her intelligence to set traps or follow leads to expose the blackmailer.
She might initially be shocked and scared. But then she would start to think rationally and try to find a way to outwit Snape. For example, she could start to gather evidence against Snape's own wrongdoings, if there are any, so that she can turn the tables on him.
In 'Hermione's Ordeal', she is initially shocked but quickly composes herself. She tries to negotiate with her kidnappers, using her wits to buy time. She also attempts to analyze their motives and weaknesses, which is very Hermione - like. She doesn't just sit there and wait to be rescued; she actively tries to find a way out of the situation.
One common plot twist could be that the blackmailer is someone she least suspects, like a fellow Hogwarts student who has a hidden agenda. For example, they might be jealous of her academic achievements and use some secret they've uncovered to try and undermine her. Another could be that the blackmail involves a dangerous magical secret she's been entrusted with, and if it gets out, it could put the wizarding world in jeopardy.
In most of these fanfictions, Hermione reacts with her characteristic intelligence. For example, in 'The Captive Hermione by Greyback', she immediately starts to analyze her surroundings and look for possible escape routes. She uses her knowledge of spells and potions to try and gain an advantage over Greyback.
Hermione could become withdrawn. She might isolate herself from her friends for a while, spending her time in the library trying to make sense of it all. She might also feel a sense of betrayal, especially if they had some sort of understanding or relationship developing.
She could also be calculating. Since she's so intelligent, she might be quickly assessing her surroundings, looking for any weaknesses in their captivity of her. She might be thinking about which spells she could use effectively in the given situation, or how to use the environment to her advantage.
Hermione would likely react with her usual intelligence and quick - thinking. She might start by trying to analyze Dolohov's motives and weaknesses. She could also try to find a way to communicate with the outside world, perhaps using magic in a very discreet way.
She could become defensive at first. After all, she's being unjustly targeted. She might start to isolate herself a bit from the Gryffindor group while she tries to find a solution. Hermione would also likely use her vast knowledge to research if there are any spells or external forces causing this. She might also seek help from other houses, like Ravenclaw, where her intelligence would be more appreciated in this situation.
She is likely to be defiant. Hermione has always been a strong - willed character. So she would probably not go down without a fight. She might immediately start looking for ways to escape or undermine Dolohov's plans.
Hermione would likely be defiant at first. She is a brave and strong - willed character. So, she would probably try to resist Narcissa's attempts to intimidate her and would look for ways to escape immediately.