A possible plot is that Sasuke is in a different dimension and Naruto has to figure out a way to travel there to save him. He might have to gather some special items or learn new jutsus to make it possible. Or perhaps Sasuke has lost his memories and Naruto has to help him regain them while protecting him from those who want to use his amnesia for their own gain. In some fanfics, Sasuke could be in a coma and Naruto uses his own chakra to try and wake him up, which could lead to some really emotional and intense scenes.
One plot idea could be Sasuke and Naruto going on a journey together outside of the Hidden Leaf village. They face various challenges like harsh weather and dangerous wild animals. Along the way, they share stories from their past and deepen their brotherly bond. Another could be Sasuke teaching Naruto some unique Uchiha jutsu in a secret training session, which shows their trust and closeness as brothers.
A really interesting plot could be that Sasuke, for some mysterious reason, is the only one who can understand baby Naruto's unique needs. Maybe Naruto has some sort of power that only Sasuke can detect as a baby. So Sasuke becomes Naruto's guardian and mentor right from the start. As Naruto grows, they form an unbreakable bond that is different from their relationship in the original series. This could lead to many new adventures and challenges for both of them, and also change the way the other characters in the Naruto world view their relationship.
One possible plot development could be that Sasuke is in a life - threatening situation, perhaps against an extremely powerful enemy. Naruto sacrifices himself to give Sasuke a chance to escape or defeat the foe. This would likely lead to Sasuke being filled with guilt and regret, and might change his whole outlook on life.
One interesting plot idea could be that in a world where Sasuke is a wolf and Naruto is a fox, they are forced to team up against a common enemy that threatens their respective clans. They start off distrusting each other but as they face challenges together, they learn to rely on one another's unique abilities.
One plot idea could be Sasuke and Sai being forced to team up on a mission. Sai, with his unique artistic abilities and Sasuke with his powerful jutsu. They start off not getting along as Sasuke is still brooding and Sai doesn't quite understand his ways. But as the mission progresses, they learn to trust each other. For example, Sai could use his ink techniques to create diversions while Sasuke attacks the real enemies from the shadows. This would show their growth as characters and how they can work together despite their differences.
One plot idea could be that they discover their brotherhood early on and train together more closely. They might combine their unique abilities, like Naruto's Rasengan and Sasuke's Chidori, to create new and powerful jutsus. This could change the whole dynamic of the story, with them facing challenges as a united front instead of rivals.
One idea could be a story where Naruto, as a mediator, tries to bridge the gap between Sasuke, representing Indra, and someone who has the spirit of Ashura. Maybe they have to work together to stop a new, powerful threat that only their combined powers can defeat. For example, a dark force that is trying to break the cycle of reincarnation between Indra and Ashura.
One idea could be that they are in the alley hiding from some common enemy. In the heat of the moment, with the tension high, they share a kiss as a sign of their deep bond that has developed over time. It could be a moment of realization for both of them about their feelings.
One plot idea could be that they are ninjas in a world where their clans are feuding. To avoid causing more conflict, they keep their friendship a secret. Another could be that they are part of a secret organization within the ninja world that has strict rules about personal relationships, so they have to hide it. Maybe they are also trying to protect each other from enemies who would use their relationship against them.
One idea could be that Naruto and Sasuke find a mysterious baby in the forest. They then have to figure out where the baby came from and how to take care of it together. This could lead to some comical moments as they struggle with diaper changing and feeding.