Often, the plot develops with a sense of mystery. His friends would start to investigate what really happened to get him sent there. There would be a search for evidence to prove his innocence. Meanwhile, Harry in Azkaban might discover some dark secrets about the prison itself or about those who sent him there.
When Harry Potter is sent to Azkaban in fanfiction, the plot development can be quite complex. First, there's the emotional turmoil of his friends and allies. Hermione would likely be pouring over every law book to find a loophole for his release. Ron would be more impulsive, perhaps trying to break in right away. Inside Azkaban, Harry has to deal with the Dementors. His willpower would be constantly tested. As the story progresses, the plot might shift towards a battle between the forces that want to keep Harry in Azkaban and those who are fighting for his freedom. This could involve political intrigue within the Ministry of Magic and some epic magical battles.
The story could develop in many ways. One way is that Harry starts to lose hope in Azkaban, but then he finds a glimmer of something that gives him the strength to fight back. Maybe he discovers a hidden passage or an ally among the inmates. Another way is that the outside world starts to change without Harry. Voldemort could be making more moves, and Hermione and Ron have to step up in different ways to deal with it while also trying to free Harry.
In such a fanfiction, perhaps Dumbledore would immediately start an investigation to prove Harry's innocence. He might call in old favors from various magical beings. Hermione would likely be at the forefront of researching ways to break Harry out legally, using her vast knowledge of magical laws.
If Harry Potter were sent to Azkaban in fanfiction, it could be a very dark turn of events. He would likely be wrongly accused, as he often is in the face of Ministry corruption. His time in prison might involve him using his magic in secret to resist the Dementors, and it could also lead to an uprising within Azkaban by other inmates who believe in his innocence. It could also prompt his friends to stage a dangerous rescue mission.
In fanfiction, if Harry Potter were sent to Azkaban, it would be a huge deviation from the original story. He would likely face extreme hardships. The Dementors there would constantly drain his happiness. His friends, like Hermione and Ron, would probably try everything to prove his innocence and break him out. It could also lead to a situation where Voldemort might gain more power without Harry being able to oppose him freely in the wizarding world.
If Harry has any special magical abilities or items that were overlooked, he could use them. For instance, if he still has the Marauder's Map, he might be able to find hidden passages in Azkaban to communicate with the outside or find evidence within the prison that clears his name. Also, his relationship with magical creatures like the Thestrals might come in handy. If they can be made to testify or help in some way, it could be a way to prove his innocence.
Maybe he uses some powerful magic spells that he has learned secretly. For example, the Patronus charm could be used to fend off the Dementors which are the main guards in Azkaban. He might also get some unexpected help from his friends or some mysterious characters within the fanfiction world.
Often, the plot develops with Harry facing new challenges in the new place he flees to. He has to adapt to a different magical culture. For example, if he goes to France, he might encounter different types of magic and different social norms among wizards there.
When Harry Potter refuses detention in fanfiction, the plot may develop in a way that Harry starts to question the entire Hogwarts disciplinary system. He could form a group of like - minded students who also have issues with the way detentions are given. This group might then try to change the system from within. Meanwhile, the faculty would be in an uproar, with some teachers seeing Harry as a troublemaker and others perhaps secretly admiring his courage. The story could then focus on the power struggle between the students and the teachers over the detention system.
In such a fanfiction, the plot might involve false evidence being planted against Harry. Maybe someone uses dark magic to create the illusion that Harry has committed a serious crime, like using an Unforgivable Curse. The Ministry of Magic, being quick to judge, sends him to Azkaban without a proper investigation. Harry would then have to find a way to prove his innocence from within the prison, perhaps with the help of his friends who believe in him and are secretly working on the outside to clear his name.
The plot could develop with Harry having to face the harsh rules of Azkaban. He might start to form alliances with other prisoners who are wrongly accused, like his father's friends perhaps. And as he grows, he starts to understand the dark secrets of the wizarding world from a different perspective, one that is filled with the pain and injustice of Azkaban.