Naruto would probably be defiant. He's not the type to just sit there and be a victim. He'd likely be shouting at his captors, telling them they made a big mistake.
He might also try to talk his way out. Naruto is good at making connections with people. He could try to appeal to the better nature of the Kumo ninja, if there is any, by sharing his dreams of peace and unity among the villages.
The Kumo ninja would likely be angry at first. They'd feel that Naruto, as a symbol of hope in the shinobi world, should have noticed their problems. But some of them might also be hopeful that Naruto's arrival would finally change things for the better. As for Naruto himself, he'd probably be shocked to realize how much he'd overlooked Kumo and would feel a sense of guilt.
If Naruto gets captured by Orochimaru in fanfiction, his friends' reactions would be intense. Hinata, who has deep feelings for Naruto, would be heartbroken but also very determined. She might try to secretly track Orochimaru on her own at first, using her Byakugan to search for Naruto. Kiba with Akamaru would be eager to jump into action, using their tracking skills. Lee would be excited to prove his strength and save Naruto, ready to use his Taijutsu skills against Orochimaru. His friends' combined efforts would be focused on rescuing Naruto from Orochimaru's clutches as soon as possible.
Naruto would probably use his friendly and outgoing nature to adapt. He'd start by getting to know the people around him, like his new family and the local ninjas. He might also be interested in Kumo's unique jutsu and training methods, which would help him fit in. And of course, he'd keep his goal of promoting peace between Konoha and Kumo in mind, which would give him the motivation to overcome any difficulties in adapting.
Well, one possibility is that Naruto's friends would immediately start a rescue mission. They'd gather all the intel they can about Kumo's defenses and where Naruto is being held. Maybe Sasuke would put aside his differences for the time being and team up with the others.
In such a fanfic, Naruto might be subjected to various interrogations by Kumo. They could be interested in his Nine - Tails power. Maybe they would try to extract information about Konoha's secrets through him.
Shikamaru, being the laid - back yet perceptive friend, would probably think that Naruto has a plan. He would be concerned but also understand that Naruto is not one to make hasty decisions without a good reason. He might keep an eye on Naruto's family in his absence and hope that Naruto will return safely one day.
A plot twist could be that Naruto discovers a long - lost connection between the Nine - Tails and some ancient power in Kumo. This could change the whole dynamic of his capture situation. Instead of being a victim, he might become an important figure in Kumo's internal power struggle. And this new - found connection could also lead to a new alliance between Konoha and Kumo in the end. Another twist could be that Naruto's capture was a ruse by Konoha's higher - ups to gain some secret knowledge in Kumo. Naruto was sent there on purpose, but things start to go wrong when Kumo figures out the plan.
At first, Naruto would be completely shocked. He has always seen Hinata as a loyal friend and someone who has deep feelings for him. So the idea of her betrayal would be hard to fathom. He might try to deny it at first.
He would be filled with rage. Naruto has a strong sense of justice and the fact that someone took Hinata away from him would fuel his anger. He would vow to find and punish whoever was responsible. He might even become reckless in his pursuit of vengeance, endangering himself and those around him. His friends would have to step in to try and bring him back to his senses.
Naruto would probably be heartbroken. He loves Hinata deeply, so finding out she might have cheated would shatter him.