The plot could revolve around their relationship growing stronger because of the pregnancy. James might become more protective of Lily. They could start making plans for their future outside of Hogwarts. For example, they might look for a safe place to live. Also, they'd have to think about how to raise their child in a world full of magic and danger. There could be a sub - plot where they try to find ancient magic spells to protect their unborn child from any potential harm.
Well, one possible plot could be that they face a lot of challenges. Their friends might be shocked at first. They'd have to deal with their studies while also preparing for a baby. And they might worry about how the Hogwarts faculty would react, whether they'd be allowed to stay in school.
One possible plot could be that Lily has to face the challenges of being a pregnant student at Hogwarts. She might have to deal with the reactions of her friends and professors. Maybe she'll try to hide it at first out of fear of being expelled or judged.
One possible plot could be that James Albus and Lily Potter are facing a new mystery at Hogwarts. Maybe they discover a hidden chamber that no one has found before and inside it are secrets about their family's past at Hogwarts. They then have to figure out how to deal with these revelations while also keeping up with their studies and normal Hogwarts life.
It could be James Potter. Since they have a relationship in the original story, it's possible that in the fanfiction, he is the father.
One idea could be that they face challenges from the wizarding world due to their relationship while Lily is pregnant. Maybe there are threats from dark forces who want to harm them or their unborn child.
One reason could be that James is simply not ready to be a father. He may be afraid of the responsibilities that come with having a child and decides to run away from them.
Voldemort and his Death Eaters could be the main antagonists. Since they are against the wizarding world's light side, they would see Lily and James's unborn child as a threat, especially if there are prophecies surrounding the baby.
Well, it could be that James and Lily are brought back through some magical time - turning spell. They meet Harry as he is now, a young hero. Harry gets to show them all he has achieved, and they are filled with pride. They might also help him solve some new, unexpected magical problem together.
Maybe it could be a time - travel plot where Ginny somehow gets to meet James and Lily Potter. For example, she could use a magical object or spell that sends her back in time. And then she might have adventures with them, perhaps helping them in some way that also has an impact on the future she came from.
It could be that Lily publicly embarrasses James in front of their friends. She might disclose some of his insecurities that he thought were private, like his fear of not living up to his family's reputation. This would deeply wound James' feelings and cause a rift between them.
A plot could revolve around the challenges they face during the pregnancy. For example, Lily might have some difficult symptoms, and James has to learn how to take care of her while also dealing with his own insecurities about becoming a father. They could also face some threats from the wizarding world's dark forces, adding an element of danger to the story.