Maybe Hermione has lost her confidence in her magical abilities due to some traumatic event. Snape, in his own gruff way, decides to mentor her. He helps her recover by guiding her through difficult spells and magical concepts she had previously mastered but forgotten. This journey of recovery could also involve them exploring parts of Hogwarts that are little - known, and in the process, they form an unlikely friendship.
Well, in some fanfictions, Hermione might use her vast knowledge of magic. She could research rare spells or potions to heal whatever ails Snape. Maybe she discovers a way to reverse the effects of a dark curse that was placed on him. For example, if the curse is sapping his strength, she might find an ancient counter - curse in the library that requires precise incantations and rare ingredients. She would then gather those ingredients, perform the spell, and slowly help Snape regain his health and vitality.
One challenge could be Snape's pride. He's a proud man and might not be willing to accept help easily. He could resist Hermione's attempts at first, seeing it as pity or interference. Another issue might be the secrecy involved. If Snape's condition is something that needs to be kept quiet, Hermione has to be very careful about who she involves and what she reveals. For example, if his ailment is related to a secret mission or some dark magic he was involved with, any leaks could put Snape in more danger.
Their relationship would likely become less antagonistic. Snape has always been tough on Hermione in the original series, but in this fanfiction, as he helps her recover, he would start to see her more as an individual worthy of respect. Hermione, on the other hand, would see Snape's kinder side and perhaps develop a sense of gratitude towards him.
One common theme is the breaking of barriers. Snape and Hermione start with a lot of animosity, so when he helps her, it's about breaking down those initial negative feelings.
In a fanfiction, perhaps Lucius Malfoy has lost his wealth and status due to Voldemort's fall. Hermione, being the kind - hearted person she is, decides to help him get back on his feet. She might use her skills in magic and her connections in the wizarding world. Maybe she helps him find a job at the Ministry of Magic in a department that could use his knowledge of the old pure - blood families' ways. This would be a very different Lucius, humbled by his circumstances, and Hermione's help could lead to a character - growth arc for both of them.
One possible plot could be that Hermione is struggling with the pressures of her studies and the ongoing battle against the Dark Arts. Snape, being a complex character, might notice her distress in his own way. Maybe he initially dismisses it but then realizes she's in a deeper state of depression. He could then use his knowledge of potions to try and help her, leading to an unexpected bond between them.
One possible plot could be that Snape discovers Hermione has been sneaking into the restricted section of the library for some research that could get her in big trouble. He threatens to expose her to the school authorities unless she does his bidding, like helping him with some dangerous potions experiments. This would put Hermione in a difficult situation as she doesn't want to break the rules further but also doesn't want to get in trouble.
One possible plot for this fanfiction is that Hermione wants revenge on the Death Eaters who have caused harm to her friends and the wizarding world in general. Dolohov, having once been a Death Eater himself, could provide crucial information about their hideouts, plans, and weaknesses. This would give Hermione an edge in her quest for revenge. He could also use his combat skills, which are no doubt formidable, to protect Hermione during her confrontations with the bad guys.
One possible plot could be that Hermione discovers a Death Eater who has doubts about Voldemort's cause. Maybe the Death Eater has a family member who was unjustly punished by Voldemort. Hermione, being the intelligent and empathetic witch she is, offers the Death Eater a way out. She could provide a safe haven or help them fake their death and start a new life away from the Dark Lord's influence.
In this fanfiction, it might be that Snape sees Harry in a vulnerable state during winter break. Maybe Harry is being bullied by some Slytherins even during the break at Hogwarts. Snape, despite his usual dislike for Harry, steps in to protect him. This action could start to change Harry's perception of Snape, and they could form an unlikely alliance. As time passes, Snape could start to share some of his own experiences with Harry, which helps Harry grow not just as a wizard but also as a person.