Perhaps in the fanfiction, Snape submits to Harry Potter in terms of teaching methods. Harry, having learned a lot from his own experiences, convinces Snape to try a more hands - on and empathetic approach with the students, leading to a transformation in Hogwarts' teaching environment.
One possible interesting plot could be Snape having to follow Harry Potter's lead in a dangerous mission. Maybe they are in a situation where Snape has no choice but to trust Harry completely, which is a big change from their usual relationship in the original books.
In some versions, Snape might submit to Harry Potter's moral code. Harry, with his strong sense of right and wrong, makes Snape reevaluate his actions and allegiances. This could lead to Snape making amends for his past wrongdoings and joining Harry more wholeheartedly in the fight against the dark forces.
Obviously, Harry Potter and Snape are the main characters. Harry, with his courage and leadership, and Snape, with his complex past and skills. But other characters like Hermione and Ron could also play important roles. They might be the ones who first notice the change in Snape's behavior towards Harry and help Harry deal with this new situation.
One interesting plot could be Harry growing up with Snape's strict but ultimately caring guidance. Snape might teach Harry potions from a very young age, and Harry could develop a different kind of magic skill set compared to canon. Another plot could involve Harry having to deal with the Slytherin side of the wizarding world earlier, as Snape has strong Slytherin ties. Also, the relationship between Harry and Snape could be a complex mix of father - son dynamic and teacher - student relationship, which would be really fascinating to explore.
Perhaps in the fanfiction, Snape assigns Harry to clean all the old potion vials in the storage room during detention. While doing so, Harry discovers an old diary that seems to hold secrets about Snape's past at Hogwarts, which then leads to a series of revelations and a change in their relationship.
Perhaps in the fanfiction, Harry is magically bound to please Snape in academic tasks. So, he has to study extra hard in Potions class and other subjects Snape is involved in. This might result in a transformation of their relationship, from animosity to a grudging respect as Snape starts to see Harry's efforts.
A really unique plot could be Snape adopting Harry during a time when Voldemort is still a threat. Snape has to balance protecting Harry from Voldemort's followers and also from the prejudice within the wizarding community. He might train Harry in Occlumency more intensively, and in the process, they develop a deeper understanding of each other. Harry starts to see Snape not as the mean professor but as a complex person with his own traumas and reasons for his actions.
One interesting plot could be Snape raising Harry while secretly training him in advanced potions and dark arts defenses. Harry would grow up with a different perspective on Snape, seeing him as a strict but caring father figure. Another plot might involve Snape having to protect Harry from other dark wizards who suspect Harry's true potential. This could lead to some intense magical battles and Snape using his knowledge and skills to keep Harry safe.
Well, a possible plot is that Harry discovers his true parentage in a very dramatic way. He could be in the middle of a battle or a difficult situation at Hogwarts and suddenly realize that Snape and Bellatrix are his parents. This would completely change his perception of himself and his place in the wizarding world. He might then have to deal with the consequences of this revelation, such as how the Order of the Phoenix and the Death Eaters view him.
At first, it could be very tense. Harry might be reluctant to submit, but as time goes on, he starts to see Snape in a different light. This could lead to a grudging respect. For example, Snape might show Harry some advanced potions techniques that no one else has taught him, which makes Harry realize Snape's value.
One possible plot could be that Harry is magically compelled to submit. Voldemort might use some dark magic or a powerful artifact to control Harry's mind. Another plot could be that Harry submits out of a false belief that it will save his friends. For example, Voldemort could deceive Harry into thinking that if he surrenders, his friends will be spared. Or perhaps Harry is so worn down by the fight that he gives in, thinking there's no other way, and then the story could explore how Voldemort uses Harry's submission to his advantage, like making Harry a tool to gain the loyalty of other wizards.
Well, some fanfictions might have a plot where Snape and Harry are forced to team up against a new dark threat in the wizarding world. Snape's knowledge of the dark arts and Harry's experience with Voldemort could create a really engaging story. There could also be a plot where Snape discovers a long - lost family connection to Harry, which completely changes their dynamic. In this case, Snape might be more protective of Harry than we would expect, and Harry has to come to terms with this new side of Snape.