Maybe Harry's anger is a result of the betrayal he feels from someone close. When he reaches Grimmauld Place, he stumbles upon a hidden room filled with old Black family magic items. These items could either help him in his fight against Voldemort or make his situation even more complicated as his anger clouds his judgment.
In this fanfiction, Harry could be angry due to the actions of the Ministry of Magic. As he arrives at Grimmauld Place, he may discover that the place holds the key to a mystery related to Voldemort. His anger might lead him to be more impulsive in his search for answers, which could put him and others in danger.
Well, perhaps Harry is angry because of some injustice he faced at Hogwarts. When he arrives at Grimmauld Place, he might find some secrets about the Order of the Phoenix that further fuel his anger. He could also have an argument with some of the residents there, like Sirius or Mrs. Weasley.
He will most likely meet Sirius Black. Sirius is an important figure in Harry's life and his presence at Grimmauld Place is quite significant. They could have a deep conversation about Harry's anger and what to do next.
Well, in fanfiction, it could be that when Harry arrives at Grimmauld Place, he discovers new secrets about the Black family. There could be hidden rooms or magical artifacts that are crucial to the fight against Voldemort. Maybe he stumbles upon a diary of one of the Black ancestors that reveals a long - forgotten spell or prophecy.
Well, the plot could involve Harry exploring the secrets of Grimmauld Place on his own. Maybe he discovers hidden rooms filled with old Black family magic items. He might also struggle with feelings of loneliness and isolation, but at the same time, use the solitude to practice his magic without distractions.
Maybe Harry has a big fight with Ron over something like Ron's lack of trust. For example, if Ron doubts Harry's intentions again as he did in the original story. Harry, in a fit of anger, kicks Ron out of Grimmauld Place.
Well, it could be about Hermione getting caught in the rain while at Grimmauld Place and then having to deal with being soaked. Maybe she has to quickly find a way to dry off and in the process, there are some interesting interactions with the other characters who are also at Grimmauld Place.
In this fanfiction setting, Snape might be at Grimmauld Place on some secret mission. Hermione, being the inquisitive witch she is, could stumble upon him. There could be a tense moment at first, but then they realize they need to cooperate. Snape could teach Hermione some advanced magic that she wouldn't learn at Hogwarts, and in return, Hermione could offer her unique perspective on the wizarding world. Their relationship could develop into an unlikely alliance, which would be really exciting to read about.
One possibility is that they are there to retrieve some Dark Arts artifacts hidden in Grimmauld Place. Lucius believes that these artifacts can strengthen their position in Voldemort's ranks. Draco, on the other hand, is starting to question the morality of using such artifacts. As they search, they come across old memories and secrets of the Black family that make Draco wonder if the path his family has chosen is the right one. He might start to see the value in the Order of the Phoenix's fight against the Dark Arts, even if he doesn't fully support them yet.
Since I haven't read this fanfiction, it's difficult to give a detailed account. However, it may be a story that uses Grimmauld Place as a backdrop for some sort of romantic or sexual plot. It could be about how the characters interact with each other in this location in a more private and personal way. It might also explore the secrecy and the unique atmosphere of Grimmauld Place and how that impacts the relationships and the sexual or romantic elements within the fanfiction.
One key event could be Harry exploring the secrets of Grimmauld Place. He might discover hidden rooms or artifacts. Another could be him hosting Order of the Phoenix meetings there, which would involve a lot of strategic discussions and planning against Voldemort.
There's a possibility that after Sirius's death, Harry just sort of took over. He had already spent time there and knew the place well. The remaining members of the Order of the Phoenix, seeing his connection to the place and his leadership potential, supported his claim to Grimmauld Place.