One plot idea could be that they discover their family connection early on. Maybe they find a hidden family tree or an old letter that reveals the truth. This could lead to them having to work together secretly to protect their newfound family bond from the wizarding world's prejudices.
Perhaps their family connection is a result of a long - lost branch of the family. Their families have been enemies for so long that when they find out they're cousins, it causes a huge stir in the wizarding community. They could then be on a journey to understand the origin of their connection and in the process, learn more about the history of their families and the wizarding world as a whole.
Another idea is that their cousin relationship is part of a prophecy. They initially resist the idea of being related but as they start to experience strange magical events together, they realize they must embrace their connection to fulfill the prophecy. For example, they might have to combine their unique magical abilities, Harry's courage and Draco's knowledge of dark magic (but for good), to defeat a new dark force.
One plot idea could be that they are forced to work together on a school project that requires them to explore each other's family histories. This makes them realize they have more in common than they thought. Another could be that they discover a secret magical realm only they can access together, and in the process, they form a bond. Or perhaps they are both framed for a crime and have to rely on each other to clear their names.
Well, in this type of fanfiction, a possible plot is that Harry is sold due to a powerful curse placed on his family. Draco, who has a change of heart over time, tries to break the curse. This could lead to a journey of self - discovery for both of them. They might also discover secrets about their families' pasts that are intertwined. Also, the situation could force them to work together against a common enemy that emerges because of Harry's new 'ownership' status.
Perhaps they were separated at birth due to some dark wizard's plot. As they grow up, they start to notice strange similarities in their magical abilities and instincts. When they find out they are triplets, they join forces to uncover the mystery behind their separation. They might face many obstacles, like opposition from their respective families who have different beliefs and values. Harry's Gryffindor - like courage, Draco's Slytherin cunning, and Blaise's own unique traits would all play a part in this adventure.
One idea could be that they discover their family connection during a magical crisis. Maybe a dark force is threatening both the wizarding world and the world of the Greek gods, and their combined powers as cousins help in the fight. For example, Harry's knowledge of complex spells and Percy's control over water could be used in creative ways to defeat the enemy.
One interesting plot idea could be that they discover they are brothers early on. They then have to deal with the shock of it within the context of the Hogwarts houses. Harry might try to bring Draco closer to his friends, which could lead to some really funny and awkward moments as Draco is used to his Slytherin clique. Another idea is that they work together to uncover secrets about their family, secrets that could change the wizarding world's view of their family's past.
In this fanfiction, perhaps Draco and Sirius have to go on the run together. Sirius has experience with being a fugitive, and he could teach Draco how to survive while being hunted. This could lead to a deep bond between them as they rely on each other for survival. Along the way, Draco could learn about Sirius's past, including his time at Hogwarts and his relationship with James Potter. This new knowledge could make Draco re - evaluate his own life and the choices he has made so far.
One idea could be that Harry and Draco find a magical toy that has the power to transport them to different wizarding worlds. They have to work together to find their way back home. Another could be that they both inherit a collection of enchanted toys from an old wizard, and they must figure out how to use the toys to solve a mystery in Hogwarts.
One idea could be that Harry and Draco find an abandoned magical baby and they have to work together to take care of it. This forces them to put aside their differences and learn about each other in a new way.
One idea could be a story where Harry, Draco, and Severus are forced to work together on a dangerous mission to save Hogwarts from a new dark threat. They start off distrusting each other but gradually learn to respect and rely on one another.
One idea could be a story where Draco, Harry and Hermione are forced to work together on a special magical project for the Ministry. They start off hating each other but gradually come to respect one another's skills. Another plot could involve them getting trapped in an alternate magical dimension where they have to rely on each other to find their way back. Maybe Draco has some knowledge of the dark magic that created the dimension, Harry has his Gryffindor courage to lead them through dangerous areas, and Hermione uses her vast knowledge to figure out how to break the spell that trapped them.