The relationship between Naruto and Sasuke is complex. In this retrieval fanfiction, their past memories together could play a big role. Flashbacks of their time at the ninja academy, their first missions, and the bond they formed could be used to heighten the drama of Naruto's quest to bring Sasuke back.
Well, Naruto would probably face a lot of tough opponents. Since Sasuke has his own goals and might be with some powerful people, Naruto would have to fight his way through. He might encounter new jutsus and strategies that he has to overcome.
Some of Naruto's former friends who have been influenced by the negative propaganda against him could also be antagonists. They might be misled into believing that Naruto has changed for the worse. They could actively oppose Naruto, either by trying to capture him or by preventing him from doing certain things. Another possibility is that there could be a hidden group within the village that has a vendetta against Sasuke and, by extension, Naruto for bringing him back.
Well, perhaps in the fanfiction, after bringing Sasuke back, Naruto discovers that there are some secrets that the village has been hiding from him all along. When he tries to expose these secrets, the village sees it as a betrayal and turns against him. He might then be forced to team up with some unexpected allies outside of the village to clear his name and fight for what he believes is right. It could also be that Sasuke's return actually brings some kind of curse or danger with it, and Naruto is wrongly blamed for it.
At first, Naruto is probably shocked and confused. He might not understand why the village would take such a harsh step just for hurting Sasuke. He may feel betrayed, especially if he thought he had friends and allies in the village.
One common theme is redemption. Naruto, being banished, often has to prove himself worthy again. And Sasuke, as a female, may play a role in his journey towards redemption. Another theme is love against all odds. Their relationship is usually complicated by Naruto's banishment, but they still find a way to be together.
One popular example could be 'The Exiled Uchiha' where Fem Sasuke is banished and has to find her own path outside of the village. It explores her character development as she faces new challenges.
They might become more reliant on each other. Since they are both banished, they are in a similar situation. They could form a stronger bond as they face the challenges of being outcasts together. For example, they would need to find shelter and food, and this shared struggle could bring them closer.
Maybe Naruto's connection to Pein through the Nine - Tails is misinterpreted. Since Pein was after the Nine - Tails, the village believes Naruto is a liability. Banished, Naruto wanders into a hidden land where he learns ancient ninja techniques that are far more powerful than what he knew. He could then return to the village as a changed and more powerful ninja, but with a sense of bitterness towards those who banished him.