Well, perhaps the US soldiers go back in time to the era of the American Revolution. They find themselves in the middle of the colonies' fight for independence. Some might try to blend in and help the revolutionaries in a more covert way, while others may accidentally expose their modern ways, causing both amazement and suspicion among the colonists. And in the process, they learn a great deal about the roots of their own nation.
One possible plot could be that a group of US soldiers are sent back in time during a military experiment gone wrong. They end up in a crucial historical battle, like the Battle of Gettysburg. They use their modern military knowledge and advanced weaponry (to a certain extent if they still have it) to change the outcome of the battle, which then has a ripple effect on the course of history.
In a 'us soldiers back in time fanfiction', they could be sent back to World War II. They might land in the European theater. They could end up working with the Allied forces in unexpected ways. For example, they could use their knowledge of modern tactics to help plan a major offensive. Or they might interact with soldiers from different countries and cultures, learning about the hardships and heroism of that time period while also trying to figure out how to get back to their own time.
A young and inexperienced soldier named Jake could be a main character. He's fresh out of basic training and is suddenly thrown back in time. His naivete in the face of this new and old world at the same time makes for an interesting journey as he has to quickly adapt. Another could be Sergeant Thompson, a tough and battle - hardened veteran who uses his experience to lead the group of soldiers in this strange time - travel situation.
One possible plot idea could be a team - up scenario. The RWBY characters might encounter a group of US soldiers in a strange, otherworldly dimension. They would have to combine their skills, with the RWBY girls using their unique combat abilities like Ruby's scythe - wielding speed and the soldiers' military tactics and weaponry to face a common enemy. For example, they could be fighting against a horde of Grimm that have somehow invaded a world that has elements of both Remnant and a modern - day Earth setting.
One possible plot could be Gohan going back in time to the Saiyan saga. He could use his knowledge of future events to prevent certain tragedies. For example, he might try to save the Saiyans from Frieza's wrath. He could also train with the younger versions of Goku and the other Z - fighters, sharing his advanced techniques and knowledge, which would significantly change the power dynamics in the battles against the Saiyans and later enemies.
Perhaps Sasuke goes back to the very beginning of his ninja training. He decides to learn different jutsu that he didn't focus on before. He could also try to understand the political situation of the village better. Since he has seen the consequences of certain actions in the future, he aims to change things for the better. For example, he might try to improve relations between the Uchiha and the rest of the village much earlier. This would involve interacting with the elders and trying to find a compromise. It could also lead to a different path for Itachi as well.
One possible plot for 'Titanic Back in Time' fanfiction is that a modern - day historian goes back in time to the Titanic. They want to study the ship and its passengers up close. However, they end up getting involved in the events on the ship. They might try to document everything in a different way, perhaps to prove some theories they had in the present. And as they interact with the people on the Titanic, they start to form deep emotional connections and struggle with the knowledge of the impending doom.
One possible plot could be that Esme travels back to a time when she was about to make a crucial life decision. For example, she might go back to the moment before she met her significant other. In the past, she could then have the chance to see things from a different perspective. Maybe she realizes that the decision she made back then was actually the best one, or she might find out new things about herself or the people around her that she didn't know before, which could lead to a whole new set of adventures and self - discovery in the past and ultimately change her view of her present life.
Well, in the fanfiction, Itachi could go back in time and decide to train his younger self more rigorously. This would not only make him stronger but also change the way he approaches his future tasks. He might also try to influence Sasuke at an earlier age, guiding him in a different direction than in the original timeline. And he could befriend some characters earlier to build a stronger support network for the Uchiha clan.
Maybe Yusei goes back in time to prevent a great disaster that happened in the past. He could use his knowledge from the future to change certain events and save lives.
In a 'kaneki goes back in time fanfiction', perhaps Kaneki goes back to when he was still a normal college student. He then decides to study more about ghouls secretly. He could use this knowledge to try and find a way to co - exist peacefully between ghouls and humans from the very start. He might start by trying to change the views of some key people in the CCG, using his understanding of their future actions.
Well, one possible plot could be that Zuko goes back in time and tries to prevent the Fire Nation's aggression from the start. He could use his knowledge of the future to change things for the better, like trying to influence his father in a different way to avoid the war.