A plotline might involve Snape being removed unjustly. His allies or some students who knew his true nature might try to fight for his reinstatement. There could also be a story where Snape's removal causes a power vacuum in Hogwarts, and different factions start vying for control of certain aspects of the school. It could also lead to a discovery of secrets that Snape was protecting while he was at Hogwarts.
Maybe it's a group of Hogwarts' own staff members. They could be jealous of Snape's influence or knowledge. They might fabricate evidence against him to get him removed. For example, some teachers who have always disagreed with his teaching style or his past associations.
One possible plotline could be Naruto feeling a great sense of betrayal. He might go off on his own journey to become stronger in a different way than in the original story. Maybe he meets new allies who help him discover new powers or techniques.
One possible reason could be that he feels he has fulfilled his purpose there. Maybe he has achieved certain goals related to protecting Harry Potter secretly, and he decides it's time to move on to other things. For example, in some fanfictions, he might leave to explore his own family history or to further his research on the Dark Arts in a more secluded place.
Perhaps in some 'harry marries snape fanfiction', there could be a magical accident that binds their fates together. At first, they resist the connection, but as they get to know each other better, they find common ground and fall in love, leading to marriage. This could involve a lot of emotional turmoil and self - discovery for both characters.
There could be a plot where Snape's muteness is a secret that he tries to hide from everyone at Hogwarts. The story could be about how he manages to teach Potions and be a double agent for Dumbledore all while keeping this secret. Or perhaps a plot where his muteness is a magical experiment gone wrong, and the story is about his journey to reverse it. Along the way, he might discover new aspects of magic and his own identity that he never knew before.
In some 'Snape slave to Harry fanfiction', the plot might start with a prophecy or a magical bargain. Maybe a seer predicted that only with Snape as Harry's servant could a great evil be defeated. So, Snape, bound by this fate, has to follow Harry's commands. Along the way, they face many challenges together. Harry has to deal with the power imbalance and Snape has to struggle with his pride. Their relationship evolves from one of forced servitude to a more complex bond of respect and cooperation as they fight against the forces of darkness.
One possible plotline could be that Snape accidentally discovers Harry is extremely ticklish and uses it as a form of mild punishment when Harry misbehaves in Potions class. For instance, if Harry forgets an ingredient or causes an explosion.
Maybe Hermione is injured while exploring some dangerous magical ruins. Snape is the only one around with the knowledge and power to heal her. As he heals her, they start to have deep conversations about magic, life, and their respective pasts, which in turn builds a connection between them.
Maybe in a fanfiction, Harry could be framed for something he didn't do, and Snape, believing the false accusations, smacks him in a moment of anger. This could then lead to a series of events where Harry tries to prove his innocence and Snape has to come to terms with his hasty action. Another plotline could be that Snape is under the influence of a dark spell that makes him act out of character, and Harry just happens to be in the wrong place at the wrong time and gets smacked.
One possible plotline could be that Harry discovers Snape's memories early on. Overwhelmed by the truth of Snape's love for his mother and his selfless sacrifices, Harry hugs Snape as a sign of immediate forgiveness and gratitude. Another could be in a post - war scenario where Snape is still alive, and Harry, now a more mature wizard, reaches out to Snape to heal old wounds.