One possible main plot could be that Naruto and Kakashi go back in time to prevent a great disaster. For example, they might aim to stop the Nine - Tailed Fox attack on Konoha that happened in the past. This would involve them having to deal with different versions of their friends and enemies. They would need to be careful not to change too much of the past, as it could have unforeseen consequences on the future they came from.
One possible main plot could be Naruto using his Anbu skills to change the past. Maybe he tries to prevent certain tragedies like the Uchiha massacre. He could secretly influence events, using his knowledge of the future and his combat abilities.
One possible plot could be Naruto using his Rinnegan powers to go back to the time when the Uchiha clan was about to be massacred. He could try to prevent it, which would change the whole future of the ninja world. He might face challenges like convincing the Uchiha not to rebel and dealing with the political powers that were behind the scenes pushing for the massacre.
A possible plot twist is that Kakashi goes back in time and finds out that the events he thought were true in the past were actually misinformation. This could completely change his perception of the history of the ninja world and his own role in it. Also, he might go back to a time when Orochimaru was just starting his dark experiments. Kakashi could try to stop Orochimaru right from the start, but in doing so, he might end up creating new villains or problems. Or perhaps, when he travels back, he loses some of his memories from the future, which makes it difficult for him to use his knowledge effectively to change things.
One possible plotline could be Kakashi using his knowledge from the future to prevent Sakumo's suicide. He might try to change the events that led to Sakumo being shamed in the village. For example, he could expose the real reasons behind certain missions' failures that were wrongly blamed on Sakumo. This would not only save Sakumo but also potentially change the entire future of the Hidden Leaf village, as Kakashi's own life and development were deeply affected by Sakumo's death.
One possible main plot twist could be that they go back to a time when the Uchiha clan was not yet massacred. Sasuke might have the chance to prevent it, but this could have unforeseen consequences. For example, it could disrupt the balance of power in the ninja world at that time. Another plot twist could be that they go back to a time when Naruto's parents were alive. Naruto might get to meet them and learn from them directly, which would change his understanding of his own identity and power. A third plot twist could be that they find out that their time - traveling was actually part of a grand scheme by an ancient and powerful enemy, who wants to use their presence in the past to change the future in a way that benefits them.
One possible plot twist could be that Dark Naruto tries to change the past to prevent his own dark transformation. He might attempt to save someone important who in the original timeline led him down the dark path. For example, if it was the death of a certain character that made him turn dark, he could go back and try to save that person. This would completely change the future and the Naruto we know from the original story.
Well, perhaps a plot twist could be that when Kirito goes back in time, he discovers that his own existence in the past was a key factor in creating the problems he faced in the future. So, he has to figure out a way to change things without erasing himself. Or, he could go back and find that the person he loves in his original timeline has a completely different personality or role in the past, which throws him off and makes his feelings really complicated.
One possible plot could be a training adventure. Naruto, Kakashi, and Iruka could go on a special mission to train Naruto further. Kakashi might teach Naruto some new and advanced ninja techniques, while Iruka could offer moral support and his own knowledge of basic ninja skills. They could face a new and dangerous enemy, and through their combined efforts, Naruto could learn important lessons about teamwork and self - improvement.
One possible plotline could be Naruto using his old and experienced self to prevent past tragedies. For example, he might stop the Uchiha massacre. He could use his knowledge of jutsu and his understanding of people to change the course of history and bring about a more peaceful future from the start.
One possible plotline could be Naruto using his newfound time - traveling ability to prevent some of the major tragedies in the past. For example, he might try to stop the Uchiha massacre. He could also use his knowledge from the future to help his younger self become stronger faster, perhaps by teaching him some advanced jutsu he learned later in life.