One possibility could be that Dumbledore arranges for Harry to live with Snape for protection. Snape, though reluctant at first, gradually discovers Harry's hidden strengths and they form an unlikely bond. Harry might learn more about his mother from Snape, which could lead to a deeper understanding between them.
One possible plot could be that they discover they are brothers early on in Harry's time at Hogwarts. Snape then has to balance his duties as a teacher and his newfound family connection. He tries to protect Harry in secret from the threats within the school, like Malfoy and his cronies.
Perhaps in the fanfic, there is some sort of magic that binds their fates together. Snape might discover this connection and, despite their past differences and his own reserved nature, he decides to propose to Harry as a way to accept this newfound bond. It could also involve Snape trying to make amends for his past actions towards Harry by offering this ultimate commitment.
One possible plot could be that after some sort of danger at Hogwarts, perhaps a new dark threat, Dumbledore decides that Harry would be safer living with McGonagall. McGonagall, being strict but fair, would impose a strict study regime on Harry. She'd also teach him some advanced magic that he might not learn in regular classes. Harry would get to see a different side of her, like her love for cats which could lead to some comical moments as he tries to interact with her Animagus form.
One possible plot could be that Snape, out of a sense of guilt or a newfound understanding of Harry's situation, decides to take him in. Snape would have to deal with Harry's grief over his parents and his own complex feelings towards the boy. He might start to teach Harry magic in a more personal and different way than at Hogwarts, leading to a unique bond between them.
The plot could be that Snape discovers he has a deeper connection to Harry. Maybe there was some magic involved in the past that bound them in a way. Snape then starts to take on a more protective role. For instance, he could interfere when Harry is in danger from some dark wizards who are still lurking after the war.
Well, it could be that Snape is wrongly accused of a great crime in this fanfic, and in the heat of the moment, someone attempts to kill him. Maybe it's a misdirected act of revenge by someone who thinks Snape is behind a series of dark events at Hogwarts. But of course, the truth might be far more complex and intertwined with the overall politics and secrets of the wizarding world.
Well, perhaps the fridge is a refuge for Harry Potter. He hides in there to escape from the Death Eaters. Inside the fridge, he finds ancient magic spells written on the ice cubes by some long - forgotten wizard. He then uses these spells to protect Hogwarts from destruction.
The relationship would be a rocky one. Snape has his past grudges against Harry's father. However, living together, they would be forced to interact daily. Harry might start to understand Snape's difficult past and Snape could see Harry's potential. There could be moments of anger, but also moments of mutual understanding, like when Harry helps Snape with some magical experiment.
Perhaps Tom Snape is a long - lost relative of Harry's father. In the fanfic, they meet by chance in the wizarding world outside of Hogwarts. They initially have some misunderstandings due to their different personalities and family backgrounds. But as they face some common enemies, like a group of dark wizards, they gradually form a bond and work together to protect the wizarding world. And along the way, they discover secrets about their family and Hogwarts that were previously unknown.
Well, it could be about Snape feeling a sense of duty. Maybe after Harry loses his sight in a battle against the Dark Arts, Snape, despite their past differences, steps in. He might start by teaching Harry new ways to navigate Hogwarts using magic that doesn't rely on sight, like advanced sonar - like spells.