One possible plotline could be that the other champions defend Harry during a false accusation in the Triwizard Tournament. Maybe they realize he's being framed and use their influence and skills to prove his innocence.
Perhaps in the fanfiction, the other champions defend Harry from the prejudice of their own schools. Since Harry is from Hogwarts, students from other wizarding schools might initially be suspicious or jealous of him. But the other champions could step in and defend him, saying that he is a worthy competitor and should be treated with respect. This could lead to a more united front among the different schools in the face of common challenges within the tournament.
Cedric Diggory would be a likely champion to defend Harry. He is from Hogwarts too and is known for his fairness and good nature. He might defend Harry because he realizes that Harry is in a difficult situation and doesn't deserve the extra hardships that are being piled on him.
Another plotline could be a champion who discovers a dark secret about the tournament's origin. They might find out that it was originally created as a means to control or manipulate young wizards, and they have to decide whether to expose it or play along to protect themselves and their friends.
One possible plotline could be Harry finding a way to break free from the cycle of abuse by relying on his friendships. For example, Hermione and Ron could discover what's going on and use their magic skills and wits to protect Harry. They might create a safe haven for him within Hogwarts, using protective spells and charms.
One interesting plotline could be Harry and Cedric teaming up to solve a mystery within Hogwarts that the teachers are oblivious to. They use their combined skills, Harry's courage and Cedric's intelligence, to figure out what's really going on. For example, they might discover a hidden chamber that has been long forgotten and holds a powerful magical artifact. Another could be that they form a study group which then turns into a deep friendship. They help each other with their studies, especially in difficult subjects like Potions and Transfiguration. And finally, they could be united in trying to improve the relations between the different houses in Hogwarts. By being friends, they show that Gryffindors and Hufflepuffs can work together and be allies, rather than just competitors in the Tri - Wizard Tournament.
A third plotline could revolve around a magical object or a special power that only Harry seems to have access to. For example, if there was a new magical amulet discovered that has a special connection with Harry. Hermione, being the knowledge - thirsty witch she is, might be jealous that Harry gets to experience and explore the powers of this amulet while she is left out. This could lead to a rift in their friendship until they figure out how to share or include Hermione in the discovery.
One interesting plotline could be them teaming up to solve a mystery within Hogwarts that neither the Gryffindors nor the Slytherins are aware of on their own. For example, a hidden chamber that has secrets about the founders that could change the way the houses interact.
A plotline could involve Harry's friendship with Cedric Diggory. In this fanfiction, they could become even closer friends as housemates. Harry might learn from Cedric's fairness and good - naturedness. They could team up to compete in some inter - house challenges that are unique to Hufflepuff. And when Cedric faces difficulties, Harry uses his Gryffindor - like courage along with his new - found Hufflepuff loyalty to support him.
One possible plotline could be Harry finding a magical way to fight back against the Dursleys' torture while still hiding his magic from the Muggle world. For example, he might use some subtle magic to make things go wrong for the Dursleys when they are being especially cruel. Another could be that his Hogwarts friends discover what's going on and come up with a plan to rescue him during the holidays. Maybe Hermione uses her knowledge of the law to find a way to legally remove Harry from the Dursleys' custody.
A possible plotline is that they are forced to work together due to their wolf mate bond in a situation that endangers the wizarding world. Maybe there is a dark magic threat that only their combined strength, as wolf mates, can overcome. This would not only test their relationship but also how the wizarding community views them. They could also face challenges from their families and friends who don't understand or accept their relationship.
One possible plotline could be Harry struggling to fit in at first. He's known for being a Gryffindor, so in Slytherin he'd face prejudice from both houses. Another could be him befriending Draco Malfoy early on and changing Draco's views. He might also discover a hidden side of Slytherin's history that helps him in his fight against Voldemort.