Well, it might be about Harry losing his glasses on an unknown island. Maybe he has to search for them while facing magical creatures and challenges specific to that island. It could also involve his friends helping him out, and in the process, they discover some long - lost secrets of the island.
Perhaps a magical creature that has made the island its territory. This creature doesn't want outsiders like Harry and his friends interfering. It sees Harry's glasses as a strange and foreign object and will do anything to keep them from leaving the island. It could be a giant spider - like creature that spins webs to trap intruders, just like the acromantulas in the Harry Potter series.
One possible scenario could be that the girl has to rely on her other senses more. Maybe she befriends an animal on the island that helps her navigate. For example, a friendly seabird could lead her to sources of food or fresh water. Without her glasses, the world around her is a blur, but she discovers a new kind of clarity in her relationship with nature.
Maybe in this fanfiction, the island is a place filled with illusions. Harry's lost glasses are not just ordinary glasses but hold some sort of key or magic. As he tries to find them, he discovers secrets about the island and its connection to his past. For example, the island might have been a place where a powerful wizard once hid something important, and Harry's glasses are somehow related to it. He has to use his wits and magic skills to overcome the illusions and find his glasses before it's too late.
Obviously, Harry Potter would be the main character as it's in his name. Hermione and Ron might also be there to help him find his lost glasses. They could use their combined knowledge and skills to explore the island.
The plot could progress with Harry using magic to compensate for his lack of glasses. For example, he could use a spell to make his eyesight better. Or, his friends could use their skills to help him. Hermione might use a spell to locate his glasses in the chaos of the brawl.
In such a fanfiction, Harry might be at a serious disadvantage. Without his glasses, he'd struggle to see clearly. His opponents could easily take advantage of his impaired vision. He might have to rely more on his other senses, like his hearing or his magical intuition. Maybe he'd cast a spell to enhance his vision temporarily, but it could backfire or be disrupted during the brawl.
She could try to find ways to signal for help. Maybe she builds a big fire or arranges rocks in a noticeable pattern. Since she can't see well, she might make some mistakes at first, like almost setting the whole island on fire while trying to make a small signal fire. But through trial and error, she eventually gets it right.
It could be that the glasses represent more than just a visual aid for Harry. Maybe they are a symbol of his identity as 'Harry Potter, the Boy Who Lived'. In the fanfiction, the realization might be part of a deeper exploration of how his appearance and the items associated with it are intertwined with his destiny. For example, his glasses could be a connection to his past, perhaps having some magical origin or significance that he was previously unaware of.
In many fanfictions, Harry Potter's glasses play an important role. Some might explore how his need for glasses affects his magical abilities. For example, a fanfic could have a plot where a spell goes wrong because his glasses were broken, leading to a series of comical or dangerous situations. It could also be a part of his identity in the fanfic world, like other characters recognizing him mainly by his glasses.