Perhaps the story could start with Hinata revealing her pregnancy to Neji. Neji is initially shocked but then quickly embraces the idea of being an important figure in the child's life. As the pregnancy progresses, they face challenges like Hinata's health issues due to her delicate state. Neji uses his skills and knowledge to find remedies and support her. They also plan for the future of the baby, thinking about what kind of ninja the child will become.
Maybe in the fanfic, they are on a mission together when Tenten realizes she's pregnant. This throws them off their game a bit as they now have to worry about the baby's safety too. They return to the village and Neji tells their friends, who are all excited and offer support. As Tenten's pregnancy progresses, they face some challenges like Tenten having morning sickness and Neji trying to balance his duties and taking care of her.
The antagonists could be some members of their own clan who oppose the union or the pregnancy for various reasons, such as concerns about bloodline purity or political power within the clan. They might try to undermine Neji and Hinata's relationship and the pregnancy.
One idea could be a story where Hinata discovers she's pregnant and is initially scared. Neji, being her protective cousin, steps in to support her. He could help her prepare for the baby by training her gently to keep her healthy during pregnancy. Another aspect could be how the rest of the clan reacts to the news. Some might be overjoyed while others may worry about Hinata's ability to still be a strong ninja.
Another plot could be that they discover their pregnancies around the same time and decide to support each other in their respective journeys. They might share their fears and hopes, like Hinata being worried about how her child will fit into the Hyuga clan's strict hierarchy and Neji being concerned about providing a good future for his child. They could then work together to change some of the old ways in the clan for the betterment of their future children.
One possible plot could be that Hinata is somehow mind - controlled. Maybe an enemy uses a powerful genjutsu on her that makes her see Neji as a threat to Naruto or to the village. Under this influence, she attacks and kills Neji, which then leads to a great deal of guilt and self - loathing for Hinata once she breaks free from the control.
Maybe there's a powerful enemy who has the ability to make people transform. Naruto gets hit and turns into Hinata and Neji. As Hinata, he tries to use her gentle fist techniques and discovers new aspects of combat. As Neji, he might get into debates with his own Naruto - self in his mind, as Neji had different views on things like destiny. This could lead to Naruto re - evaluating his own beliefs.
One possible theme could be family loyalty. Given their relation as part of the Hyuga clan, the fanfiction might explore how their relationship affects their loyalty to the clan. Another theme could be love and sacrifice. Neji was always very protective of Hinata in the original series, and this could be expanded upon in a romantic context in the fanfiction.
One possible plot could be a forbidden love story. Since they are from the same clan, there might be some clan rules against their relationship. So they have to keep their feelings a secret until they can't hold back anymore and share a kiss. Another plot could be that Hinata is in danger and Neji saves her, and the relief and pent - up emotions lead to a kiss.
One common theme is family and clan dynamics. Since they are from the same clan, a lot of fanfics explore how their relationship is affected by the expectations and traditions of the Hyuga clan. For example, some fanfics show them struggling against the arranged marriages within the clan to be together.
One common theme is family loyalty. Given their shared clan background, many fanfics explore how they balance their loyalty to the Hyuga clan with their personal feelings for each other. For instance, they might have to make decisions that could either strengthen or strain their relationship in the context of clan politics.