Maybe in the fanfic, Black Cat gets framed for a crime she didn't commit. Spiderman initially suspects her but then realizes she's innocent. They then work together to find the real culprit, while also exploring their complex relationship along the way. For example, Black Cat might be a bit annoyed that Spiderman didn't trust her at first, but they gradually grow closer as they solve the mystery.
One idea could be that Black Cat steals a valuable item, and Spiderman has to track her down. But when he finds her, they discover a bigger threat together and have to team up to stop it.
One plot idea could be that Black Cat steals a powerful artifact which has the potential to disrupt the balance in New York. Spiderman has to team up with her reluctantly to stop the chaos it might cause. Along the way, they start to understand each other's motives better and develop a complex relationship.
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.
One idea could be that the baby has some of Spider - Man's powers and Black Cat's agility. Maybe the baby gets into little adventures in the city, like accidentally web - swinging into a building under construction. And Spider - Man and Black Cat have to work together to keep the baby safe while also protecting their secret identities.
A plot could involve a strange device that affects their powers. Spiderman and Black Cat have to figure out how to reverse it while also dealing with their relationship. For example, the device could make Black Cat's bad luck powers go out of control, and Spiderman has to use his wits and strength to keep them both safe and also find a way to fix the situation. This would add an interesting layer to their relationship as they rely on each other more.
A possible fanfic storyline is that Black Cat is framed for a crime she didn't commit, and Spiderman has to prove her innocence while also dealing with his own doubts about her. This could involve a lot of detective work and tense moments between them.
A territorial dispute could be another plot. Black Cat has been operating in a certain part of the city for a while, and Catwoman moves in. They start a battle of wits and skills to see who gets to claim the area as their own hunting ground for valuable items. This could involve a series of rooftop chases and close - quarter combat scenes in the city's seedy alleyways.
One plot idea could be that Catwoman and Black Cat team up to steal a valuable artifact that has been causing chaos in the criminal underworld. They start off as rivals, each with their own motives, but as they work together, they begin to respect and even like each other.
One idea could be a story where Spiderman has to team up with his greatest enemies to fight a new, more powerful threat from outer space. This would force him to put aside his differences and find common ground with the likes of Doctor Octopus and Green Goblin.
In such fanfics, the Black Cat is often depicted as a very alluring and mysterious character. She might be more assertive in her relationship with Spiderman, especially if the 'pegs' concept implies some sort of power dynamic.
One idea could be that Spiderman has to face a new villain who is somehow related to the events that led him to go 'Back in Black'. Maybe this villain has a personal vendetta against Peter Parker specifically during this dark phase of his life.