In a 'Marge Saves Harry' fanfic, the plot could start with Harry ending up in Springfield for some reason. Marge discovers him and his magical abilities. When she learns of the threats he faces in his own world, she decides to accompany him back to the wizarding world. Once there, Marge uses her homemaking skills in a creative way. For instance, she could use her cooking skills to make potions or her knitting skills to create magical items that help Harry in his fight against evil. Along the way, there would be a lot of cultural clashes between the Muggle - like Springfield values and the wizarding world's traditions, which would add an interesting dynamic to the story.
One possible plot could be that Aunt Marge, surprisingly, has a change of heart. She starts to see Harry's potential and decides to take him in. She might try to 'muggle - ize' Harry, making him fit into her more ordinary world. This could lead to many comical situations as Harry tries to adapt to her rules while still having his wizarding side peek through now and then.
One possible plot could be that Marge, despite her initial rough exterior, discovers a soft spot for Harry. She might start to teach him some of her own values, which could be a mix of traditional and rather strict ones. Harry would have to adjust to living in a new environment with Marge's dogs and her no - nonsense attitude.
Well, it could be that Hedwig is poisoned by some magical substance. Harry, with the help of Hermione's research skills, figures out what the poison is. He then goes on a quest to find the antidote. Along the way, he faces many challenges like dangerous magical beasts and tricky spells. But in the end, he gets the antidote and saves Hedwig just in time.
Well, perhaps Harry uses his magic skills like the Patronus charm to fend off some dark force that is attacking the Avengers. He could also use his knowledge of potions to heal any injured Avengers.
A unique plot could be that Bart discovers a time - traveling device in the attic. He accidentally takes Marge with him to the past, and they have to find a way to get back. Along the way, they meet a younger version of Homer and other Springfield residents from the past. This adventure would show a different side of their relationship as they rely on each other to return home.
One possible plot could be that Aunt Marge discovers Harry's difficult situation at the Dursleys and decides to secretly help him with his magic studies. Maybe she has a change of heart after seeing how much he's struggling.
Well, perhaps Daphne somehow discovers Harry's awful situation at the Dursleys. She might use magic to break into the house secretly. Then she could use a spell to make the Dursleys forget about Harry so that she can take him away without a fuss.
Maybe the story shows Harry coming across Luna being bullied in a secluded part of Hogwarts. He steps in bravely, using his reputation as the 'Boy Who Lived' to intimidate the bullies into leaving Luna alone. He might also comfort Luna afterwards and form a stronger bond with her.
Well, perhaps in this fanfic, Harry notices Draco in a dangerous situation with Buckbeak. Maybe Draco was taunting Buckbeak and it got out of hand. Harry, being the brave one, steps in and uses his skills with magical creatures to calm Buckbeak down just in time to save Draco from getting seriously hurt.
Perhaps in this fanfic, Severus doesn't just save Harry physically from the Dursleys. He also saves Harry from the emotional and psychological damage that the Dursleys have been inflicting on him. Severus, having his own traumatic past, might be able to relate to Harry on a deeper level and starts to mentor him in ways that Dumbledore never could. This could lead to a completely different Harry, more confident and less impulsive.