Well, it could start with a common goal. Maybe they all have to face a really powerful dark force together. So, despite their past differences, they put aside their grudges. For example, in a situation where Hogwarts is in great danger from an ancient evil. Harry, Draco and Lucius might realize that they need to combine their skills and knowledge to save the school. Draco could bring in his knowledge of the Slytherin secrets, Lucius might contribute with his experience and connections, and Harry with his Gryffindor courage and his friends' support.
It could be that Draco has a change of heart first. He might get tired of the dark path his father Lucius has been leading him on. He starts to admire Harry's bravery and sense of justice. And then he tries to convince his father to change too. Lucius, who loves his son, might be influenced by Draco and gradually start to form an alliance with Harry for the greater good.
The Malfoy family's reputation would take a big hit among the pure - blood families. Many of them would see Lucius as a traitor for befriending Harry. But some of the more open - minded pure - bloods might start to think differently. As for the Gryffindors, some would follow Ron's lead and be hostile, while others, like Neville, might be more open to the idea. After all, Neville has also seen the good in people who were once considered enemies.
One interesting fanfiction could be 'The Unlikely Bonds'. In this story, it explores how their relationships develop in a way that defies the typical animosity shown in the original series. It shows Harry, Snape, Lucius and Draco coming together due to a common threat to the wizarding world. They start to understand each other's motives and gradually form a sort of alliance, which eventually turns into an unexpected friendship.
Their relationship can develop realistically through shared experiences outside of their usual Hogwarts cliques. For example, if they volunteer for a dangerous but important mission in the wizarding world. This would force them to rely on each other and see past their initial biases. Another way is if they discover a common interest, like a rare magical creature or a forgotten branch of magic. It would give them a reason to interact more and gradually build a connection.
Hermione could be a great addition. She could be the voice of reason when Harry starts getting closer to Lucius. Her intelligence and knowledge of magic could also help in any situation they face together. Another good character would be Draco. Since Lucius is his father, it would add an interesting dynamic. Draco could be conflicted about his father's new relationship with Harry. And of course, Dumbledore. His wisdom and guidance could play a crucial role in how the relationship between Harry and Lucius develops.
Perhaps a mutual friend like Hermione could play a role. She might set up a situation where Draco and Harry have to work together on a project. At first, they would be reluctant, but as they start to see each other's positive qualities, like Draco's determination and Harry's loyalty, they begin to respect each other and a friendship could form.
One plot idea could be that they are both cursed by a dark wizard and they have to rely on each other to find the cure. This forces them to put aside their differences and work together.
One idea could be a story where they are forced to work together on a dangerous mission for the wizarding world. They start off distrusting each other but gradually come to respect one another as mates. Harry's courage, Snape's cunning, and Lucius's ambition could combine in interesting ways to overcome the challenges.
Suppose there's a Tri - Wizard Tournament - like event at Hogwarts. Harry's sister and Draco are both chosen as representatives for their houses. They are forced to train together. At first, they are constantly bickering, but as they face the challenges together, they learn to trust and rely on each other. This shared experience could be the foundation for a deeper relationship.
Draco could start as his usual haughty self, looking down on the pizzeria work. But as he faces challenges like dealing with difficult customers or learning to make pizza properly, he could gradually become more humble. For example, when a customer complains about the pizza being too cold, instead of his usual snappy retort, he tries to fix the problem and learns about customer service.
Well, their relationship could be developed differently by having Lucius be more vulnerable with Draco. Instead of always being the strict, cold father, he could open up about his own fears and insecurities. For instance, Lucius could share his concerns about the future of the Malfoy family in the changing wizarding world.