Maybe Emily Brown is an undercover Auror sent to Hogwarts to investigate some dark magic rumors. Snape, being the complex character he is, is initially suspicious of her. However, as they start to work together to uncover the mystery, they gradually understand and respect each other. Their relationship could develop through shared secrets and dangerous encounters.
Another plot could be set in a post - war scenario. Emily Brown, who has some unique healing abilities, comes to Hogwarts to help the students recover from the traumas of the war. Snape, who has his own past to deal with, is initially resistant to her help. But through her kindness and determination, she manages to break through his walls and they develop a bond that helps both of them heal.
One possible plot could be that Emily Brown is a new student at Hogwarts and Severus Snape initially has his usual cold demeanor towards her. But as she shows an extraordinary talent in Potions, he starts to take a special interest in mentoring her. This could lead to a deep friendship or even more as they face challenges together in the wizarding world.
For Snape, his character could be developed further by showing his reactions to Emily's presence. He could gradually open up more of his softer side, which was mostly hidden. For example, he might start to share his memories of Lily Potter with Emily as he begins to trust her.
Some unique plots include a fanfic where Snape and Harry are magically bonded and can feel each other's emotions. There's also a story where Snape is turned into a cat and only Harry can understand him, leading to some really interesting interactions. A different one is a fanfiction where Harry discovers that Snape was actually protecting him all along in a much more elaborate and secret way than in the original books, and they have to team up to expose a greater conspiracy within the wizarding world.
In some fanfictions, her plot could revolve around time - travel. She might accidentally travel back in time and meet her father when he was a student. This would give her a chance to see a different side of him and understand his choices better. She could also try to change some events in the past to make a better future. However, this would bring a lot of consequences and she would have to deal with the butterfly effect in the wizarding world.
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.
One popular plot is the redemption arc of Severus Snape through his relationship with Hermione. In these stories, Hermione might see a side of Snape that others don't and help him come to terms with his past actions.
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.
Some plots might involve Snape being forced to confront his new - found relation to Voldemort in the middle of the wizarding war. For example, he could be captured by Voldemort's forces and Voldemort reveals the truth to him. Then Snape has to decide whether to embrace this new identity or fight against it. There could also be a plot where other characters like Harry and Hermione suspect Snape's relation to Voldemort and try to prove it.
One interesting plot could be that Snape secretly follows Harry during a dangerous wizarding tournament task and intervenes when a dark creature is about to attack Harry without revealing his identity. This would add a layer of mystery and show Snape's hidden care for Harry.
One plot could be that Snape, under some dark magic influence, forces Harry to accompany him on a dangerous mission to retrieve a lost magical artifact. Snape believes Harry has some hidden power that can help. Another could be Snape forcing Harry to study a very advanced and dangerous form of magic, thinking it will protect Harry in the long run. And there could also be a plot where Snape forces Harry to enter a magically sealed area to face some long - forgotten threat that only Harry can potentially defeat.
A good Severus Snape fanfiction often has a deep exploration of his character. Since he's such a complex figure in the original series, fanfics that really dig into his motives, his love for Lily, and his relationship with the other Hogwarts characters are great. For example, stories that show his interactions with Harry from a different perspective can be really engaging.