Perhaps in the fanfiction, the bathhouse is a magical place where Naruto and Sasuke's memories are shared. They see each other's childhood traumas and it makes them understand each other on a deeper level. They then make a pact to protect each other more fiercely in the future while in the relaxing atmosphere of the bathhouse.
Well, it could be that the bathhouse is a neutral ground where Naruto and Sasuke are forced to meet by some outside force. At first, they are hostile, but as they soak in the warm water, they start to let their guards down. They talk about their different paths and how they both still care about the Hidden Leaf. And by the end of their time in the bathhouse, they have a newfound respect for one another.
Shikamaru could be a supporting character. He might be the one who sent Naruto and Sasuke to the bathhouse area as part of a strategic plan for a mission. He could be waiting outside and making snarky comments when they come out. Another could be Sakura. She might be worried about Sasuke being in the bathhouse with Naruto and come to check on them, causing some comical moments.
A plot could be that Sasuke's sister discovers a hidden power within herself that could either save or destroy the ninja world. Naruto and Sasuke have different views on how to handle this situation. Naruto wants to help her control it for good, while Sasuke is more cautious. This creates a conflict between them and also gives the sister a central role in the story, as she has to decide her own fate.
A great plot could be that Sasuke, in the reversed role, is the village's hope. He is the one everyone looks up to. Naruto, with a dark past that led him to be bitter, is on a path of self - destruction. Sasuke tries to stop Naruto from causing harm to himself and others. He uses his own positive energy and the power of friendship to make Naruto realize that there is more to life than revenge. This would be a complete role reversal from the original Naruto and Sasuke dynamic.
A cool plot could be that a new villain emerges who has the ability to nullify the powers of the Sharingan and Rinnegan. Naruto and Sasuke have to find a way to overcome this without relying solely on their eye powers. They might discover ancient techniques that their predecessors used before the existence of these eye powers.
One interesting plot could be that Sasuke's sister has a unique power that both Naruto and Sasuke are unaware of. She could be a key to uniting the Hidden Leaf Village and the Uchiha clan in a new way. Maybe she has the power to heal the rift between the village and the remaining Uchihas after the massacre. And as Naruto and Sasuke are on their own paths of growth, she emerges as a bridge between them, helping them understand each other better.
Well, it could be about Naruto wanting to show his care for Sasuke through cooking. Maybe he tries to make Sasuke's favorite dishes to bring back old memories and re - kindle their friendship.
One possible plot could be that Naruto and Sasuke are on a mission together in this fanfiction. Naruto might ride on Sasuke's back as they are escaping from a powerful enemy. They could be in a situation where Naruto has been injured and Sasuke is using his speed and strength to get them to safety.
Perhaps Sasuke has been influenced by some dark force. This force could be manipulating him into believing that Naruto is a threat to his goals. So, he kidnaps Naruto to either stop him from interfering or to convert him to his side. It could lead to a very intense struggle within Naruto to resist Sasuke's influence.
Well, one possible plot could be that they decide to live together to train more intensively. They might share their different jutsu knowledge, like Naruto teaching Sasuke about Sage Mode and Sasuke teaching Naruto some of his unique Uchiha techniques. This would lead to them becoming even stronger together.
The plot might start with Sasuke attacking the village again, but this time with a more sinister plan. Naruto, who has always tried to bring Sasuke back, finally snaps. He realizes that Sasuke is too far gone. Naruto's revenge could be a long - drawn - out process. He first has to figure out Sasuke's motives and weaknesses. He might team up with some unlikely allies, like Orochimaru who also has a history with Sasuke. Their encounters would be full of intense combat, with Naruto determined to make Sasuke pay for his actions.