A fanfic could be set in a post - Avengers world. Bruce and Natasha decide to take a break from the superhero life and go on a road trip. During the trip, they discover new things about each other. Bruce learns about Natasha's past in more detail and Natasha sees a different side of Bruce that is not just the 'Hulk'. They have deep conversations and their friendship might turn into something more romantic.
Perhaps a fanfic where Bruce accidentally creates a device that messes with time. Natasha gets caught in the time - distortion and Bruce has to go back in time to save her. In the process, he sees different versions of Natasha at different points in her life. This gives him a new perspective on her and when he finally saves her, their bond becomes unbreakable.
One idea could be a story where Bruce and Natasha are on a mission together in a remote location. They have to rely on each other's skills to survive. Bruce uses his scientific knowledge to figure out a way to stop a dangerous experiment gone wrong while Natasha uses her combat skills to protect them from the threats around. Their relationship gradually deepens as they face challenges side by side.
In a fanfic, there could be a plot where Natasha is poisoned and the only antidote can be created by Bruce using his knowledge of biochemistry. But he has to do it while keeping the Hulk in check. As he races against time, Natasha's condition worsens. This creates a tense situation that tests their relationship and shows how much they mean to each other. They also share some tender moments during this difficult time.
Another theme is redemption. Natasha might see helping Bruce control the Hulk as a way to redeem herself for her past actions. And Bruce might see Natasha as a chance at a normal life, which is a form of redemption for him. It's a complex interplay that is explored in a lot of the fanfictions.
Their love story began with understanding. Natasha saw beyond the Hulk in Bruce. She knew he was a brilliant scientist with a good heart. Bruce, in turn, saw Natasha's strength and vulnerability. They had a bond that grew over time. For example, in some missions, they relied on each other's skills. Their relationship was about more than just romance; it was about two people finding solace in each other in a world full of chaos and danger.
The love story of Bruce and Natasha was captivating because of their mutual growth. Bruce learned to trust more because of Natasha, and Natasha found a different kind of purpose in being with Bruce. They both had their own demons. Bruce with his fear of the Hulk getting out of control and Natasha with her past as a spy. But together, they seemed to be able to face those demons better. It was like two broken pieces fitting together to form a whole. Their relationship also had an air of mystery as they were both so different, and it was exciting to see how they would interact each time.
The fanfiction 'Banner and Romanoff: Unlikely Allies' is also quite good. It starts with their professional relationship in the Avengers and then slowly evolves into something more. It has some really interesting character interactions and a well - paced plot that keeps you engaged.
How about 'Natasha Romanoff x Male Reader: A Shared Adventure'? This title gives the idea that the two characters will go through something together, which is a common theme in fanfics. It also clearly shows the relationship between Natasha Romanoff and the male reader that the fanfic will focus on.
Another fanfic concept could involve Harry Potter somehow ending up in Bruce Banner's world. He might be there to learn about modern Muggle technology and end up meeting Bruce. Together, they could face a threat that requires both magic and scientific knowledge to defeat. For example, a villain who is using both dark magic and advanced technology to cause chaos.
A plot could involve a scientific experiment gone wrong that only Banner and Romanoff can fix together. As they work on it, they start to see each other in a new light. Maybe there are some strange side - effects of the experiment that make them experience emotions more intensely, leading to a romantic connection. For example, they might be exposed to a chemical that heightens their senses and makes them more aware of their attraction.
Another idea is that Percy gets thrown into the Marvel universe and Natasha is the first one to find him. She initially thinks he's some kind of new super - powered threat but soon realizes he's from a different realm. They then have to figure out how to get Percy back home while also dealing with the various threats that are attracted to Percy's presence in the Marvel universe.
One great 'Natasha Romanoff fanfic' is 'Red Room Echoes'. It delves deep into Natasha's past in the Red Room, exploring her training and the relationships she had there. The character development is really well - done, making it a captivating read.