Perhaps he's being dragged by a group of bullies, like Draco Malfoy and his cronies. Since he can't see clearly without his glasses, he's having a hard time defending himself. This could lead to a situation where he has to rely more on his other senses and magic skills to get out of the predicament.
One possible scenario could be that he's being dragged by some dark magic force in a forbidden part of Hogwarts. Maybe he lost his glasses during a fight or while being chased, and now he's in a vulnerable state. Without his glasses, his vision is blurry, adding to the sense of danger and confusion.
For the drama. It creates a sense of vulnerability for Harry. His glasses are an important part of his identity, and without them, he's at a disadvantage. This can heighten the tension in the story.
It could be a situation where Harry has been wrongly accused. Some overzealous magical law enforcers chain him up and confiscate his glasses as a form of punishment before a proper trial. This would create a lot of internal conflict within Harry, feeling betrayed by the very system he has been fighting for.
Perhaps in the fanfiction, Harry discovers a new spell or a magical item that can temporarily enhance his vision without glasses. But there could be a catch, like it only works for a short time or has some side - effects. This would lead to a whole adventure of him trying to find a more permanent solution while also dealing with the normal challenges in the wizarding world.
One possible plot twist could be that without his glasses, Harry has trouble recognizing his captors or his surroundings clearly. This could lead to some miscommunications or misunderstandings. For example, he might mistake a friendly wizard trying to rescue him for another captor. Another twist could be that the kidnappers took his glasses to specifically weaken him, as he is so used to seeing the magical world clearly with them. They could be using it as a psychological tactic to make him feel more vulnerable and off - balance.
Another idea is that some Death Eaters find Harry without his glasses in a vulnerable state. They start by taunting him about his weakness without the glasses. Then they use dark magic to make him experience extreme pain, like a searing pain in his eyes as if they are trying to make him feel the 'punishment' for relying so much on his glasses. They might also try to force him to perform difficult magic tasks without being able to see clearly, and punish him severely when he fails.
One possible plot twist could be that without his glasses, Harry has a hard time recognizing his captors. It might turn out that they are people he thought he could trust, like some seemingly friendly Hufflepuffs who are actually under the Imperius Curse. This would add an element of betrayal and confusion to the story.
It could be part of a magical curse. The curse made him lose his glasses and trapped him in a cage. Maybe it was cast by a jealous student at Hogwarts who wanted to get back at Harry for always being in the spotlight. In the cage, Harry has to figure out how to break the curse and get his glasses back, all while dealing with the limitations of his impaired vision.
It could be really interesting. Maybe without his glasses, Harry would seem more vulnerable, and Malfoy might take advantage of that in a different way than in the original story. They could have more intense eye - to - eye confrontations that are different from the ones where Harry is hidden behind his glasses.
Perhaps in this fanfiction, Harry is in a cage as part of a magical experiment. Some rogue wizards are trying to study how a wizard's magic is affected without their usual aids, like Harry's glasses. In the cage, Harry discovers new aspects of his magic that he didn't know before. He could start to manipulate the magical energy around him in different ways, even without clear vision, and eventually break free from the cage and confront those who put him there.
In this fanfiction, Harry without his glasses could be in a situation where he is forced to rely on his friends more when dealing with Horcruxes. His vision impairment without glasses makes it difficult for him to be as independent as he used to be. So, Hermione and Ron play a more crucial role. For example, when they are searching for a Horcrux in a dark and dangerous place, Harry has to trust their descriptions completely. And as they progress, Harry discovers that the Horcruxes are affecting his vision in a magical way, and he has to find a way to break this spell while still trying to destroy the Horcruxes.