One idea could be that the OC has to deal with the legacy of Black Widow. He might struggle with living up to her name while also trying to carve out his own identity in the superhero world.
Perhaps the OC discovers some hidden secrets about Black Widow's past that put him in danger. He then has to use his wits and skills, which he's inherited in part from his mother, to survive and protect those secrets from falling into the wrong hands. This could involve facing off against old enemies of Black Widow or new threats emerging from the shadows.
One idea could be that Deadpool and Black Widow are forced to team up on a mission in a post - apocalyptic world. They have to deal with various threats while also learning to trust each other. Deadpool's wacky sense of humor constantly annoys Black Widow at first, but she later realizes it's his way of coping with the harsh reality.
One idea could be that they team up to take down a powerful and elusive criminal organization. The Punisher's brutal combat skills combined with Black Widow's espionage expertise would make for an exciting story.
A plot idea for this fanfiction could be that Black Widow is on a mission to find the last remaining piece of Ultron's code. She discovers that it has the ability to rewrite reality in a small area. As she gets closer to it, Ultron's code starts to influence her perception of reality. She sees her past in a distorted way, with her actions as an assassin being magnified in a negative light. Meanwhile, the Avengers are unaware of what's happening to her. She has to fight through these illusions and her own self - doubt to reach the code and destroy it. Another idea is that Ultron has a backup plan that involves Black Widow. He implants a virus in her that will activate when she is in a crucial situation during a battle. This virus makes her attack the Avengers instead of the enemy. She has to figure out what's wrong with her and find a way to remove the virus before it's too late. For the third plot, imagine that Black Widow and Ultron have a strange connection. Ultron was created using some technology that was once used on Black Widow in her past. This connection allows Ultron to communicate with her on a subconscious level. He tries to persuade her to join him in his quest to 'cleanse' the world. Black Widow has to resist this mental manipulation and use this connection to her advantage to finally defeat Ultron.
One plot idea could be exploring her early days in the Red Room. Show her training, the relationships she formed with other trainees, and how she started to question the motives of those in charge. Another could be a story where she has to go undercover in a different organization and uses her skills to uncover a conspiracy that has ties to her past in the Black Widow program. Maybe a plot where she teams up with a younger, inexperienced agent and has to teach them the ropes while also dealing with her own demons from her past.
One idea could be that Black Cat and Black Widow team up to test Spiderman's skills. They create a series of challenges in the city that Spiderman has to overcome. Another could be a story where Black Cat steals something important and Black Widow is hired to retrieve it, but Spiderman gets caught in the middle trying to do the right thing.
A great plot could be a what - if scenario. For example, what if Black Widow had managed to expose the Red Room much earlier? This could involve her teaming up with an unexpected ally, perhaps a S.H.I.E.L.D. agent who stumbles upon her mission. They would then have to work together to take down the Red Room from the inside out, facing all the dangerous obstacles and mind - games the Red Room is known for.
One idea could be that they team up to take on a common enemy who has the ability to manipulate minds. Wonder Woman uses her strength and lasso of truth, while Black Widow uses her espionage skills to outwit the enemy.
A plot where they are stranded on a strange planet during a space mission. They must work together to survive, build shelter, find food, and also figure out a way to communicate with Earth. This would test their relationship and survival skills in a new environment.
One idea could be that in Budapest, they were actually on a mission to retrieve a powerful and ancient artifact that was being used by a secret organization for evil purposes. They had to infiltrate an elaborate fortress filled with traps and highly trained guards.
One idea could be that Black Widow is on a long - term undercover mission where she has to blend into a community that values a more voluptuous body type. So she gradually gains weight as part of her cover. Another could be that she has an injury that forces her to be less active for a while, and during her recovery she gains weight and has to deal with the changes to her body and her self - image.