In a fanfiction where Naruto is sealed away, there could be a focus on the emotional turmoil of his friends and family. Hinata, for example, might be extremely distraught and use her Byakugan in new ways to try and find Naruto. Sasuke could also return to the Leaf Village out of loyalty to Naruto and join the efforts to unseal him. The story could also explore how the younger generation of ninjas, inspired by Naruto's legacy, strive to become stronger to free him.
One possible plot development could be that the village is in great danger from an enemy too powerful to defeat directly. Naruto, seeing no other way, seals himself away to act as a last - line - of - defense deterrent. If the enemy tries to completely destroy the village, Naruto's sealed power could be unleashed to counter them.
One possible reason could be a misjudgment by the Hokage. Maybe they believe Naruto's power is too dangerous and uncontrollable at a certain point, so they decide to seal him away to protect the village. For example, if Naruto's Nine - Tails' power starts to go berserk and they see no other way to stop it without harming him too much.
One possibility is that the story could focus on how the village copes without Naruto. Maybe there would be a different kind of unrest or a search for a new way to deal with the Nine - Tails' power. Without Naruto, characters like Iruka might have a different role, perhaps becoming more involved in trying to find a solution to the power void.
Well, perhaps in this fanfiction, the Avatar enters the Naruto universe and causes some sort of imbalance. Naruto, seeing the chaos it might bring, decides to seal away the Avatar. As time passes, Naruto starts to learn more about the Avatar's world and realizes that there are good things about the Avatar too. So he begins a journey to find a way to unseal the Avatar without causing more harm, all while facing enemies who want to use the situation for their own gain.
One possible reason could be that his godlike powers were seen as a threat. The village elders or some powerful forces might have feared that Naruto, with his immense strength, could lose control and cause destruction. So, they decided to seal him away to protect the village and the world at large.
One possible plot development could be that Naruto gains a whole new level of power and is able to see and understand the world in a different way. He might be able to use the Rinnegan's abilities to finally bring true peace to the ninja world. For example, he could use the power of the Rinnegan to better understand the motives of his enemies and find non - violent solutions to conflicts.
A plot could develop where Naruto and Tsunade try to keep the pregnancy a secret at first. As the pregnancy progresses, it becomes harder to hide. Naruto may start to train even harder to prove himself worthy of being a father and to protect his unborn child. Tsunade, on the other hand, might face challenges from the medical community as her pregnancy at her age could be considered high - risk. And there could be a rift in their relationship as they deal with the stress and the different ways they approach the situation.
In some fanfictions of this kind, the wolf sealed in Naruto might have a past connection to a long - lost clan or an ancient evil. This could lead to Naruto uncovering secrets about the ninja world that were previously unknown. Maybe the wolf was sealed for a reason related to protecting a powerful artifact or prophecy, and Naruto now has to deal with the consequences of that.
One possible plot development could be that Kushina's spirit somehow manages to break through the boundaries between the afterlife and the living world. She then tries to communicate with Naruto, perhaps through dreams at first. This could lead to Naruto starting to search for a way to bring her back permanently, involving him in some sort of ancient and dangerous ritual that he discovers in some long - forgotten scroll.
One possible plot development could be Naruto using his new jutsu to break Yugito free from an enemy's trap. Another could be that Naruto's words break Yugito's negative mindset.