One interesting plot development could be them teaming up to solve a mystery at Hogwarts that neither could solve alone. Maybe there's a hidden magical artifact that has been causing strange things to happen, and their combined knowledge of different parts of the school and different magic techniques helps them figure it out.
Well, it could be quite a shock to the other students. Some might be very skeptical at first. For example, Harry's Gryffindor friends like Ron might be really suspicious of Draco's intentions. They've had so many bad experiences with him in the past. But as time goes on, if they see that Draco is sincere in his new - found friendship with Harry, some might start to warm up to him. Hermione, on the other hand, would probably be more open - minded and try to encourage the positive aspects of this friendship. It could also make the Slytherins view Harry in a different light, perhaps with less hostility as he is now associated with one of their own in a friendly way.
In some fanfictions, their secret friendship begins during an unexpected event, like getting lost together in the Forbidden Forest. They realize that they are not so different from each other. Draco may see that Harry is not just the 'Chosen One' but a normal boy with fears and insecurities, and Harry may see that Draco is not all about pure - blood supremacy. This new understanding could lead to a secret pact to protect each other from the real threats at Hogwarts, like the Death Eaters or other dark forces that might target them.
One possible reason could be a newfound understanding between them. Maybe they've both grown and realized that their past enmity was pointless. They might have had some shared experiences that made Harry see Draco in a different light, and thus he was willing to accept his hand as a sign of peace or new friendship.
They might start as cautious allies. They would be testing the waters, not fully trusting each other yet but knowing they need to work together. For example, they could be sharing information about certain spells or magical artifacts that are relevant to their new situation.
In some fanfictions, Draco and Harry's friendship starts with a shared experience outside of their Hogwarts house rivalries. Maybe they get lost in the Forbidden Forest together and have to rely on each other to get out. This forces them to see each other in a new light, beyond just being a Slytherin and a Gryffindor.
In many fanfictions, Draco and Harry's friendship often starts from an unexpected encounter. Maybe it's a situation where they have to work together for a common goal, like saving Hogwarts from a new dark threat. At first, they're hesitant and full of distrust because of their past rivalry. But as they get to know each other better, they start to see the good in each other. For example, Draco might show his loyalty and intelligence that Harry never noticed before, and Harry's courage and kindness could also change Draco's view of him.
The contrast between their characters makes it really interesting. Harry is known for his selfless heroism, while Draco has been a bit of a bully. Seeing them become friends challenges the pre - set notions we have of them. It's like two opposing forces coming together.
Often, it's portrayed as a slow - building process. Draco has to overcome his pure - blood prejudice, and Harry, Ron and Hermione have to look past Draco's past behavior. In some fanfictions, a common enemy or a magical mystery brings them together. For instance, a cursed object in Hogwarts that only they can solve the mystery of.
One great Draco Harry friendship fanfiction is 'The Unexpected Bond'. It shows how they gradually overcome their initial enmity and form a true friendship. They start by having to work together on a school project and discover they have more in common than they thought.