In this fanfiction, the secret girlfriend could be a new student who has some sort of special power or a mysterious past. Harry is drawn to her because of her uniqueness. They have to keep their relationship a secret because there are dark forces at work in the wizarding world that might use their relationship against them. Harry has enough on his plate already with Voldemort, and this new relationship adds another layer of complexity to his life.
Well, maybe the story could be about how Harry meets this girl in a hidden corner of Hogwarts, perhaps in the Forbidden Forest during one of his adventures. They start to secretly exchange letters and meet in the dead of night. They keep their relationship under wraps because they fear how their friends and the wizarding world might react.
It could be a Muggle - born witch who he meets outside of Hogwarts during the summer holidays. She's not part of the typical wizarding society he's used to, so they keep it a secret as it's an unusual situation for a wizard like Harry to be involved with a Muggle - born in such a way.
One possible plot could be that his girlfriend is a transfer student from a different wizarding school. She stands out not only because of her size but also her unique magical abilities. Harry is initially intrigued by her and they start a friendship that gradually turns into a relationship as they face various magical threats together.
In some fanfictions, it could be a character from another magical school. Like a girl from Beauxbatons or Durmstrang. She might have met Harry during an international magical event and they've been secretly seeing each other ever since.
There could be an original character created just for the fanfiction to be Harry's secret girlfriend. Writers often introduce new characters to add new plotlines and romantic interests for the main characters.
One possible plot could be that Harry has to keep his relationship a secret because of the wizarding world's conservative views. He and his boyfriend might meet in secret places like the Forbidden Forest. They would have to be careful not to be discovered by their friends and classmates who might not understand their relationship at first.
A plot could involve a symbiote attaching itself to Harry. This symbiote might have its own motives. It could be from another dimension where magic and symbiotes are intertwined. The symbiote could start influencing Harry's actions, making him more aggressive in his fight against Voldemort. But at the same time, his friends are suspicious of the changes in him. As the story progresses, Harry has to learn to control the symbiote and use its power for good while also dealing with the internal struggle of not losing himself to it.
Maybe Harry is at a Quidditch match. He's flying high in the air on his broomstick, but suddenly he feels the urge to pee. He can't just fly down to the loo in the middle of the game. His teammates notice his distracted state and wonder what's wrong with him. It could lead to some interesting interactions among the Gryffindor team members as they try to figure out what's up with Harry while still playing the game.
Perhaps the plot could be that the child of Harry Potter gets sent back in time accidentally. There, they meet a young Harry and his friends. The child has to be very careful not to disrupt the past too much while also trying to find a way back to their own time. This would be filled with lots of tricky situations, like when they almost reveal future events or when they have to avoid being seen by their own young parents.
In a Harry Potter has a son fanfiction, the plot could involve the son inheriting his father's magical abilities and facing new threats at Hogwarts. Maybe he discovers a hidden chamber that holds a powerful and dangerous magic. He might also have to deal with the pressure of being Harry Potter's son, with everyone having high expectations of him.
The plot could involve Harry finding the scythe in a hidden chamber at Hogwarts. Maybe it was left there by an ancient wizard, and the scythe has the power to cut through dark magic. Harry then has to learn how to use it to fight Voldemort in a new and unexpected way.