A possible plot could be that Harry and Nagin are both chosen for a special task in the wizarding world. They initially clash due to their different personalities but gradually learn to work together and form a strong bond along the way.
Maybe Harry and Amelia are from two different worlds. Harry is from a world of magic and Amelia from a non - magical world. They accidentally cross paths when a magical portal opens up. They then have to learn about each other's worlds and help each other out in various situations, such as Amelia helping Harry understand non - magical technology and Harry showing Amelia the wonders of magic.
Perhaps in the fanfiction, Vernon discovers a hidden magical talent of his own. Harry, upon finding out, has to decide whether to help Vernon develop it or keep it a secret from the wizarding world as Vernon is a Muggle. This could lead to a lot of comical and tense situations.
One idea could be a time - travel plot where Harry goes back in time and McGonagall is much younger. They form an unexpected bond during a dangerous situation at Hogwarts that gradually turns into a deeper, more romantic relationship. But they have to keep it a secret due to the age difference and the rules of the wizarding world.
Perhaps Loki and Harry find themselves in a situation where they have to swap powers for a day. Loki has to deal with Harry's magic wand and spells, while Harry has to handle Loki's shape - shifting and illusions. This could lead to a series of comical and also character - building moments as they learn from each other.
Perhaps in a Hogwarts where the normal rules are a bit more lax for a short time. Harry accidentally stumbles into Trelawney's classroom during one of her more intense divination sessions. She mistakes his presence as a sign from the stars. This leads to them spending more time together, and gradually feelings develop. They might go on a secret adventure within the castle grounds, exploring hidden chambers while their relationship blossoms.
Nagin is the other main character. Although not from the original series, in this fanfiction, she is likely to have her own unique traits and storylines.
One possible plot idea could be that Harry discovers a hidden talent that his mom had when he stumbles upon an old diary of hers. Another could be them going on a magical adventure together in a hidden part of the wizarding world.
A plot could revolve around Hermione starting a research project in Vegas. She's interested in the way magic is used in the entertainment industry there. Harry and Ron come along to support her. Along the way, they meet a group of local wizards who are being exploited by a powerful wizard entrepreneur. The trio decides to help these local wizards stand up for their rights and also uncover a plot by the entrepreneur to use dark magic to boost his business.
One plot idea could be that Harry discovers a hidden diary or memory of Lily Evans that has something to do with a lemon - scented charm she was working on. This could lead him on a journey to understand more about his mother's magic and her relationship with certain elements in the wizarding world. Maybe the lemon - scented charm has some special power that can help Harry in his fight against the dark forces.
Maybe in the fanfiction, Aunt Lemon has a hidden magical past herself. So when Harry comes to live with her, she starts to teach him some ancient spells that she learned long ago. This would add an interesting layer to their relationship as they bond over magic that is different from what Harry learns at Hogwarts.