In a 'Harry Potter x One Piece' summoned fanfiction, it could start with a powerful spell gone wrong in the wizarding world that sends some key Harry Potter characters to the One Piece universe. The Straw Hat pirates would be both amazed and confused by the magic these new arrivals possess. Luffy might be eager to have them join his crew, seeing their unique powers as a great addition to their adventures.
Well, one possible plot could be that Doflamingo somehow gets transported to the Harry Potter universe. He might initially try to take over the wizarding world using his devious powers. The female Harry Potter character could be the one to oppose him, using her magic skills and knowledge of the wizarding world. Maybe she teams up with some of Doflamingo's enemies from One Piece who also end up in the same universe.
Well, perhaps in this fanfic, the Goblet of Fire might summon Harry in a different way than in the original story. Maybe it has a mind of its own and specifically targets Harry for a more dangerous and secretive task that the original Triwizard Tournament didn't include.
Perhaps in this fanfiction, Naruto is on a mission in his own world when a strange portal opens and leads him to the One Piece universe right where Robin is. At first, they are both cautious of each other. But as they learn about their respective powers and goals, they decide to join forces. Maybe there's a common enemy that is threatening both the ninja world and the pirate world, and together they strive to defeat it.
They might be summoned by a powerful magical creature. This creature could be in need of their help to solve a problem in the magical world. It could be a dragon that has lost its way or a unicorn that is being hunted by dark forces, and they are the only ones who can save the situation.
Well, perhaps Harry could face unexpected magical challenges. The Goblet might summon him for a task that is far more dangerous than the Triwizard Tournament in the original story.
In this fanfiction, perhaps Harry Potter would be in a state of great confusion when summoned by the queen. He might initially think it's some kind of dark magic trick. Maybe he'd be worried about leaving his wizarding world duties behind. And he'd likely be very curious about the Muggle royalty.
In a Mihawk x Boa fanfiction, the plot could revolve around a mission. Let's say the World Government tasks Mihawk with keeping an eye on Boa because they suspect she might be planning something against them. Mihawk, being the stoic character he is, accepts the mission. Boa, on the other hand, quickly realizes she is being watched. At first, she tries to get rid of Mihawk, but he proves to be a difficult adversary. As time passes, they start to understand each other's motives. Boa's reasons for her actions might be related to protecting her island and people, and Mihawk might start to respect her for that. This could lead to a change in their relationship from one of animosity to mutual understanding and maybe even love.
One idea could be that Harry Potter somehow ends up in the One Piece world. He could use his magic skills to help the Straw Hat crew in battles. For example, his invisibility cloak might come in handy during a stealth mission against a powerful enemy.
Another plot could involve a wizard or witch from the Harry Potter world being sent to the One Piece world. They could have to adapt to the pirate life, learn about Devil Fruits, and use their magic in unexpected ways. For example, Hermione could use her knowledge and magic to help the Straw Hats solve some complex problems on their journey.
One possible plot could be that the Hogwarts students accidentally discover a magical portal that leads them to the One Piece world. Harry, Hermione, and Ron find themselves on the Going Merry and have to team up with the Straw Hat Pirates to find a way back home. Along the way, they learn about Devil Fruits and how they compare to magic. Harry could be intrigued by Luffy's ability to stretch, seeing it as a unique form of magic. And Hermione might study the different cultures and technologies in the One Piece world, comparing them to the wizarding world.