Well, without having read the 'harry sues the order fanfic' it's hard to say precisely. However, it could involve Harry having a conflict with an order that he believes has wronged him. This could be related to magic, or some other element depending on the nature of the fanfic's setting. It might also explore themes of justice, power struggles, and individual rights within the context of this fictional world.
You can try searching on popular fanfic websites like Archive of Our Own (AO3) or Fanfiction.net. These platforms have a large collection of fanfics and there's a good chance you might find it there.
In this fanfic, Harry could be suing the Ministry over their education policies. For example, Hogwarts might be facing some unfair regulations that are harming the students' learning experience. Harry, having a strong sense of justice, takes on the Ministry. He might gather support from other students, teachers, and even some of the wizarding families who are also affected by these policies. He would then present his case in a wizarding court, which could be full of all sorts of magical procedures and challenges.
Hermione would most likely be one of his top allies. She's smart and well - read in wizarding law, so she could help Harry build his case. Ron would also be there for moral support and to offer his own unique perspective on things.
Hermione would most likely support Harry. She's always been his loyal friend and would see the injustice of the Daily Prophet's actions. She could help him research laws in the wizarding world (if there are any regarding slander or privacy) and also use her intelligence to find ways to counter the newspaper's claims.
Another possibility is that the wizarding legal system or a corrupt official within it could be the main antagonist. They might be trying to make things difficult for Harry, or perhaps they are in cahoots with the Weasleys and are trying to cover up the Weasleys' misdeeds. This would add an interesting layer of complexity to the fanfic.
Perhaps Harry sues the Weasleys because he believes they misused some of his fame for their own financial gain. For example, they might have used his name to promote their joke shop without his permission. And Harry, being fed up with this exploitation, decides to sue them to set things straight.
Maybe Harry Potter sues the Ministry for false accusations or for not taking proper actions against dark forces. It could also be about some new laws the Ministry made that directly harm Harry or his friends.
Maybe Harry sues the Daily Prophet for spreading false rumors about him, like making up stories that he's secretly working for Voldemort again. It could be that these false reports are ruining his reputation and causing problems in his relationships at Hogwarts and in the wizarding community.