One possible plot could be that Harry is facing a new and powerful dark wizard threat in the wizarding world. He might need help from his friends, Hermione and Ron, to figure out the wizard's motives and weaknesses. Maybe he also needs the help of some long - forgotten spells or magical artifacts to defeat this enemy.
The magical creatures could play a role in helping Harry. For example, the centaurs with their deep understanding of the stars and magic could offer their wisdom. The house - elves, like Dobby (if he's alive in the fanfic), might use their unique magic to assist Harry in a time of need.
One possible plot could be Naruto facing a new and powerful enemy that he can't defeat alone. Maybe an ancient evil has been awakened and Naruto needs to seek help from old foes turned allies, like Gaara and Sasuke. He might also need to learn a new jutsu or power in order to stand a chance against this threat.
In the world of Harry Potter fanfiction, Harry might need help in various ways. For example, he could need help dealing with a new dark wizard threat that the original books didn't cover. Maybe he's struggling with his post - war trauma and needs the support of his friends more than ever. Another possibility is that he's in a situation where he has to learn a new and difficult magic spell to save someone he loves, but he can't seem to master it on his own.
In this fanfiction, Harry could be in a situation where he is magically linked to Tony Stark. Due to this link, he gains access to the concept of the arc reactor. He then tries to recreate it in the wizarding world with the help of Hermione's research skills and Ron's practical knowledge. They face many challenges as the wizarding world doesn't understand this Muggle technology at first. But eventually, they manage to build an arc reactor - like device that has the power to disrupt dark magic, which they use to defeat Voldemort in a completely unexpected way.
One possible plot could be that Harry has some sort of post - war trauma from all the battles he's been through. The service dog could be trained to sense his panic attacks and help him calm down. For example, when he has nightmares about Voldemort, the dog wakes him up and stays by his side until he feels better.
One possible plot could be that Arnold is facing some kind of academic trouble. Maybe he's struggling with a difficult subject at school like advanced math or a complex science project. His friends could then come together to try and help him out. They might organize study sessions or find a tutor for him within their group.
Perhaps Hermione is injured in a fight against dark wizards while on a secret mission. Snape discovers her and, despite their past differences, decides to help. He uses his skills in dark magic knowledge to counteract the dark spells that have injured her. This could lead to a begrudging respect between them as they work together to heal her and keep the situation a secret from other Hogwarts students and staff.
Maybe Harry discovers something about his past, perhaps related to his parents, that only Snape can help with. Snape was closely associated with Harry's parents. He might know some secrets or have some information that could help Harry understand a family mystery or some hidden power within him.
Snape could be very sarcastic and cold at first. He might taunt Harry about finally coming to him for help. However, as he realizes the gravity of the situation, he could start to take it more seriously and actually use his skills and knowledge to help Harry. For example, he might say something like 'Potter, so you've finally realized that you're in over your head and need my help? Well, don't expect me to hold your hand.' But then he would still start to investigate the problem.
Let's say Harry needs help in a fanfiction where he's wrongly accused of a crime he didn't commit at Hogwarts. His friends would need to rally around him to prove his innocence. Hermione would use her research skills to find evidence that clears Harry's name, while Ron would stand by his side and defend him physically if needed. It would be a story about loyalty and the fight against false accusations.