Well, it could be about them running away to avoid some dark magic threat at Hogwarts. Maybe a new dark wizard has emerged and they don't trust the school's ability to protect them at that moment.
One possible plot is that they run away because they get framed for something they didn't do. For example, they might be wrongly accused of stealing powerful magical artifacts. So, in order to clear their names and find the real culprits, they decide to run away and do their own investigation. They would have to rely on their friendship and the skills they've learned at Hogwarts to survive on the run and solve the mystery.
They could have an adventure where they stumble upon a hidden magical creature sanctuary. They might need to help protect it from poachers or some other danger.
In fanfic, one reason could be that he might feel constantly in danger at Hogwarts. With all the dark forces targeting him, he could think running away is the only way to keep his friends safe. For example, if Voldemort's followers keep infiltrating the school, Harry might feel responsible and decide to leave to draw the danger away from others.
In a 'Harry and Hermione run away fanfic', they could be running away from the pressure of their pre - destined roles. Harry is always seen as the 'Chosen One' and Hermione as the brilliant sidekick. Fed up with these expectations, they decide to run away and explore the wizarding world on their own terms. They might travel to different wizarding schools across the globe, learning new spells and making new friends outside of Hogwarts.
Maybe they run away because they are tired of the constant danger at Hogwarts. They've faced so many threats, and they just want a break. So they run to a peaceful place where no one knows them.
Well, perhaps they run away to escape the chaos at Hogwarts. Maybe they've discovered a dark secret within the school that puts their lives in danger. So they decide to flee and find a hidden place in the Forbidden Forest to stay safe.
One possible plot could be that they run away to escape the dark forces that are taking over the wizarding world. They might be on a quest to find a powerful magical artifact that could turn the tide of the battle. Along the way, they face various challenges like dangerous creatures and spells.
One possible plot could be that Harry and Daphne run away to escape the chaos of the wizarding world. Maybe they are tired of the constant danger and politics. They find a secluded place, perhaps a hidden cottage in the Forbidden Forest. There, they learn to live off the land, grow their own food, and discover new magic away from the prying eyes of others.
One possible plot could be that they run away to escape some dark magic threat that Voldemort's remaining followers are planning. They might go into hiding in a remote wizarding village, where they have to learn to fend for themselves without the help of the Order of the Phoenix. Along the way, they could discover new magical abilities or ancient spells that help them in their fight against the dark forces.
Well, perhaps they run away because of a misunderstanding within the wizarding community. Harry and Fleur might have been wrongly accused of something, like stealing a powerful magical artifact. So they decide to flee and clear their names on their own terms. They journey through different magical lands, encountering various magical creatures along the way that either help or hinder them.
Maybe he wants to escape the constant danger in the UK wizarding world. Voldemort's followers might still be a threat even after his defeat, and France could seem like a safe haven.