At first, Harry would probably be extremely confused and distrustful. He's been told all his life that Voldemort is the bad guy. But as Voldemort continues to protect him from the Dursleys, Harry might start to question what he knows. He could gradually become more open to listening to Voldemort's side of the story.
Maybe Draco discovers a hidden weakness of Voldemort. Draco, having been raised in a pure - blood family, might have access to some ancient magic knowledge. He uses this knowledge to create a situation where Voldemort is temporarily incapacitated, giving Harry the chance to escape or defeat Voldemort. For example, he could find a way to disrupt Voldemort's connection to his Horcruxes for a short time.
In some fanfictions, Draco might have a change of heart due to his hidden feelings for Hermione. He could use his knowledge of the Death Eaters' plans and Voldemort's weaknesses to rescue her. Maybe he has some secret magic or an unexpected alliance that helps him get to Hermione just in time.
One possible plot could be that Voldemort realizes Harry's importance in a different way. Maybe he sees that Harry has some power or knowledge that could be useful to him in the long run. So, instead of wanting to kill Harry, he decides to rescue him from the Dursleys to gain his trust and manipulate him later. For example, Voldemort might think that Harry has a connection to some ancient magic that only he can access, and by saving him, he hopes to get access to it through Harry.
Well, perhaps Harry uses his quick thinking and his knowledge of magical creatures. He might step in just in time, using a spell to distract Buckbeak before it can harm Draco. For example, he could use a simple levitation spell to lift a small object and draw Buckbeak's attention away from Draco.
In this fanfiction, Harry might also save Draco by appealing to Lucius' sense of self - preservation or family. He could threaten to expose some of Lucius' secrets or illegal activities if he doesn't let Draco go. Or, if there is some underlying family drama involved, Harry could use that to his advantage. For instance, if there's a feud within the Malfoy family that Harry is aware of, he could manipulate the situation in a way that makes Lucius back off and leave Draco unharmed.
One motivation could be self - preservation. Draco might realize that if Voldemort kills Harry, it will lead to an all - out war that could destroy everything he knows. By saving Harry, he hopes to find a more peaceful solution and protect his own family and the wizarding world in a broader sense.
Well, Harry might save Daphne from Draco because Harry is always the hero type. He doesn't like Draco's pure - blood supremacist attitude. Daphne could be a target of Draco's cruel remarks or actions just because she might not fully conform to Draco's ideas. Harry, being the defender of the underdog in many cases, steps in. Also, it could be that the plot of the fanfiction is building a new alliance or relationship web, and Harry saving Daphne is a key part of that, leading to new story developments.
It could be part of a plot where Draco is given an assignment by someone in the wizarding world to save Harry from the Dursleys. He initially does it for self - serving reasons like getting in good with certain powerful wizards who are concerned about Harry's well - being. But during the process, he actually starts to care about Harry.
One common theme is redemption. Harry saving Draco can be seen as Draco getting a second chance, especially if he was in a situation related to his past wrongdoings. It gives him a chance to change.