Perhaps the fanfic could center around a prophecy that is being hidden in the Ministry. Lucius wants to get his hands on it for Voldemort, and Harry is unknowingly in the middle. In Harry's fifth year, he starts to suspect something is wrong with the Ministry's handling of certain artifacts. As he investigates, he crosses paths with Lucius, and a battle of wits ensues as they both try to reach the prophecy first.
The plot might involve Lucius trying to infiltrate the Ministry from within during Harry's fifth year. Harry, with his natural inclination to oppose the Dark forces, gets wind of Lucius's plan. Harry then teams up with some of his friends, like Hermione and Ron, to stop Lucius. They might have to face various Ministry - related obstacles, such as corrupt officials who are in league with Lucius, while also dealing with the regular challenges of being fifth - year students at Hogwarts.
A possible plot could be that Lucius, through his connections in the Ministry, manages to frame Harry for a serious crime. Harry then has to prove his innocence while also uncovering Lucius's true motives and his ties to the Dark Lord. It could involve a lot of sneaking around in the Ministry corridors and using magic to outwit Lucius's plans.
One possible aspect could be the power dynamics. Lucius, being a Death Eater, has a complex relationship with the Ministry. In Harry's fifth year, the Ministry is in a state of denial about Voldemort's return. Lucius might be trying to manipulate the Ministry's actions for Voldemort's gain while Harry is fighting against the Ministry's false narrative. This could create intense and interesting plot points in the fanfic.
One possible plot could be that Harry is assigned to a special task force within the Ministry. He might be working on solving a mystery related to dark magic artifacts that are being smuggled. Along the way, he has to deal with the bureaucracy and some old - fashioned Ministry officials who are skeptical of his methods.
Ron could be Harry's ally as well. Despite his sometimes clumsy nature, he's loyal and has his own areas of expertise, like wizard chess which could be metaphorically applied to some strategic decision - making in the Ministry. Additionally, some of the younger, more progressive Ministry employees who are inspired by Harry's heroics could also side with him and be his allies in any changes or projects he undertakes within the Ministry.
One possible plot could be that they accidentally get exposed to a magical spell or potion that causes the unexpected pregnancy. This then throws their fifth - year studies and their relationships with friends like Ron into chaos as they try to figure out how to deal with it while keeping it a secret from most of Hogwarts.
Well, perhaps Harry has finally had enough of the Ministry's corruption and inefficiency. So he decides to take it down using his powerful magic skills. He might start by exposing all the dark secrets hidden within the Ministry walls, which could lead to chaos and the downfall of those in power.
One possible plot could be that Harry discovers some deep - seated corruption within the Ministry. He starts by gathering evidence secretly. Then, he uses his skills and the help of his friends to expose the wrongdoings in a very public way, perhaps through a magically - enhanced news broadcast that reaches every wizarding household, causing great embarrassment to the Ministry officials involved.
In this fanfiction, it could be that a new law is passed in the wizarding world. The law states that anyone with the ability to defeat a dark lord must be executed to prevent them from becoming a dictator in the future. Harry, being the only one known to have defeated Voldemort, is targeted by the Ministry. He has to rely on his old Hogwarts allies and some unexpected new friends within the Ministry to fight this unjust law and save his own life.
Maybe Harry Potter decides to sue the Ministry because they have been withholding important information about his family or his true destiny. It could also be that the Ministry has been unjustly persecuting him or his friends, and he decides to take legal action within the wizarding world's framework.
One possible plot could be that Harry grows up in the Malfoy family. He might be treated differently from Draco, as he has different values. This could lead to internal family conflicts. Harry could try to use his influence within the family to change their dark views. Maybe he secretly helps the Order of the Phoenix while still being part of the Malfoy family.
It could be that Lucius is under the orders of Voldemort. Voldemort wants Harry alive but in his control, so he sends Lucius to kidnap Harry. Lucius might then keep Harry in some secret location, perhaps an old Malfoy manor cellar, guarded by dark magic spells. Harry would then have to find a way to escape, maybe by using his own unique magic abilities or with the help of his friends who eventually figure out where he is.