It could be that after a great battle, Harry Potter decides to retreat to the woods to heal both physically and mentally. While in the woods, he stumbles upon a hidden magical community that has been living there in isolation for centuries. He then becomes part of this community, sharing his knowledge of the outside wizarding world and learning their unique ways of magic which are deeply connected to nature.
The Weasley family, if they found out about Harry's situation. Ron, being his best friend, would surely want to help. They could bring him food and supplies. Also, Dumbledore, in his mysterious ways, might be looking out for Harry from afar and send some help in the form of magical objects or even magical creatures to protect him.
Well, perhaps the plot could be that Harry is on the run from some dark forces and the trunk becomes his only safe haven. He might have enchanted it to be much larger on the inside, like the Room of Requirement. Inside, he could have all his essentials, his school books, his owl, and a little bed. He uses magic to keep it hidden and moves from place to place without being detected.
Well, one possibility could be that Harry discovers a hidden magical island. He might find new magical creatures there and learn unique spells to survive. Maybe he builds his own little wizarding home on the island.
One possible plot could be that Harry is turned into an animal, like a stag, which is his Patronus. He then has to navigate the wizarding world in this new form. He might use his animal instincts to discover hidden secrets or evade his enemies. For example, he could sneak into places unnoticed as an animal, which he couldn't do as a human. He might also communicate with other magical animals in a way he never could before, and they could help him on his quests.
Well, one possibility could be that Harry goes to France to study at Beauxbatons. He might make new friends there, like a French wizard who introduces him to the unique magical traditions of France. He could also get involved in some mystery related to an ancient French magical artifact.
Maybe Harry discovers a hidden magical community in the forest. He could learn new spells from the forest creatures and use them to protect Hogwarts later.
Well, in this fanfiction, Harry might be drawn to Australia because of some hidden magical lore. He could discover ancient Australian magic that is different from what he's used to in Europe. He might even make new friends among the Australian wizarding community and learn their ways of magic, which could be more in tune with nature compared to the more formal magic in Britain.
The plot could involve Harry exploring the castle's secrets. Maybe he discovers hidden chambers filled with ancient spells and artifacts left by his ancestors.
Maybe in this fanfiction, the attic is a secret place where Harry discovers some hidden magic. It could be a place he goes to escape the chaos of Hogwarts sometimes and study unique spells on his own.
In this fanfiction scenario, Harry Potter might be sent to Alaska as part of a special mission. The Ministry of Magic in Britain could be interested in the unique magical properties of Alaska. He could find ancient magic there that is related to the land and ice. He has to adapt to the different climate and culture while also dealing with any magical mysteries or challenges that come his way. For example, there could be a powerful magical artifact hidden in an Alaskan glacier that he has to find and protect.