It could also be that Draco is being controlled or influenced by some dark force that makes him kidnap Hermione. Zabini, being his accomplice, goes along with it at first. But as they interact with Hermione, they both start to break free from that influence. This would show a transformation in their characters as the story progresses.
For Hermione, her character would be fighting against this unjust situation. She would be using her wits to try and escape. Meanwhile, Draco and Zabini may start to have second thoughts as they see Hermione's strength and determination. Maybe Draco's motivation changes from self - interest to a more complex mix of respect and fear for Hermione.
One idea could be that Draco and Zabini kidnap Hermione for some sort of political gain in the wizarding world. Maybe they think her knowledge or influence can be used to their advantage. For example, they could be part of a group that wants to change the power structure at Hogwarts and believe Hermione holds the key to making it happen.
In some fanfictions where Draco kidnaps Hermione, his motivation could be related to family pride. The Malfoy family has long - held grudges against the 'Muggle - born' status that Hermione represents in the wizarding world. He might see kidnapping her as a way to assert the superiority of pure - blood wizards. Another possible motivation could be jealousy. Draco may be jealous of Hermione's intelligence and close relationships with Harry and Ron. By kidnapping her, he could try to break those bonds and prove himself more powerful.
At first, Hermione would be shocked. But then, she would quickly compose herself. She could play along with Draco and Blaise for a while, pretending to be compliant while she actually gathers information about their motives and the place where they are holding her. She might also try to turn them against each other by highlighting their differences in goals or personalities. Given her intelligence, she would surely come up with a clever plan to get out of the situation.
One possible motivation could be that Draco has changed. He might have seen the error of his ways and decided to do the right thing. Another motivation could be that he has feelings for Hermione, even if they are not fully realized yet. He doesn't want to see her in a bad situation, so he steps in.
Maybe Draco is jealous of Hermione's intelligence and abilities. In the fanfiction world, he could think that by making her his wife, he can somehow take credit for her achievements or keep her from outshining him. It could also be a power play. Draco might believe that having Hermione under his control through marriage would give him more influence in the wizarding world, especially if she has connections that he wants to use for his own gain.
One motivation could be that Draco has developed feelings for Hermione. So, when he sees Viktor as a rival for her attention or a threat to her safety, he takes action to save her.
Draco could be seeking redemption. He may be tired of being on the wrong side of the war. Saving Hermione, who is a symbol of the good side, would be a significant step in his journey towards redemption. Additionally, he might be influenced by his friendship or alliance with some of the other characters who are on the side of the Order of the Phoenix. They could have convinced him to do the right thing and save Hermione from Bellatrix.
Draco's motivation in prison could be to clear his name. He's a proud Slytherin and wouldn't want to be known as a criminal. His reaction to being in prison might be one of initial shock and anger. He might lash out at the guards or other inmates at first.
One plot idea could be that Draco and Blaise kidnap Hermione as part of a misguided attempt to gain some sort of leverage in the wizarding war. Maybe they think they can use her knowledge to find a way to end the conflict on their terms. Another could be that they believe she has a hidden power or secret that they want to uncover for their own gain. For example, they might think she has a connection to a powerful magical artifact that they are desperate to get their hands on.
In this fanfiction, Zabini could develop in several ways. At first, he may seem like a typical villain, but as he spends more time with Hermione, he realizes the error of his ways. He could have a backstory that is revealed, explaining why he got involved in the kidnapping in the first place. Maybe he was forced into it. As the story unfolds, he might grow to respect Hermione and even fall in love with her, which would completely transform his character from a kidnapper to a protector.