One idea could be that Spider - Man and Harley Quinn team up to take on a common enemy in Gotham. Maybe a new villain who has a technology - based power that's affecting both New York and Gotham. Spider - Man's acrobatic skills and web - slinging combined with Harley Quinn's unpredictability would make for an exciting dynamic.
Another plot could involve Harley Quinn getting lost in New York and Spider - Man helping her find her way back to Gotham. Along the way, they encounter various street - level threats and have to work together to overcome them. This could also lead to some humorous exchanges as they come from very different worlds.
A more complex plot could be that Harley Quinn is on a mission to redeem herself and teams up with Spider - Man to fight against a criminal organization that has ties to both their pasts. This would require them to trust each other and share their own stories of how they got to where they are, leading to a deeper understanding between the two characters.
Maybe Harley Quinn discovers some dark secret about Nightwing's past that she uses to blackmail him into helping her with a heist. But as they work together, they start to understand each other better. Nightwing realizes Harley isn't all bad and Harley sees that Nightwing has his own demons. In the end, they might even become friends or something more.
One idea could be Harley Quinn trying to reform herself and Batman being reluctantly drawn into helping her. Maybe she has some crucial information about a new villain in Gotham and in exchange for her safety and a chance at a new life, she offers to work with Batman.
One plot idea could be that Deadpool and Harley Quinn team up to take on a common enemy, like a new super - villain in Gotham who has a connection to some of Deadpool's foes. They could start off not getting along because of their different personalities, Deadpool's fourth - wall - breaking and Harley's chaotic - cute nature. But as they face challenges together, they learn to work as a team and even become friends.
One idea could be a story where Harley Quinn tries to break free from the Joker's control completely and starts her own life of crime without him. She could form her own gang and prove that she's more than just the Joker's sidekick.
One plot idea could be that Spiderman and Harley Quinn team up to take on a common enemy in Gotham. Maybe a new villain emerges who has technology that can disrupt both of their cities, so they have to combine their skills. Another could be a story where Harley Quinn, being a bit of a wild card, accidentally gets transported to Spiderman's New York and they have to figure out how to get her back while also dealing with the chaos she causes.
One idea could be that Harley Quinn and Deadpool team up to take on a common enemy who has been causing chaos in both their worlds. They could start off as reluctant partners, with Harley being annoyed by Deadpool's constant chatter and Deadpool finding Harley's craziness a bit much at first. But as they fight side by side, they learn to appreciate each other's skills and form an unlikely friendship.
One idea could be that Harley Quinn somehow ends up in the wizarding world. Maybe she mistakes Hogwarts for a really strange asylum at first. She could then start causing chaos with her wacky personality and unique fighting style, which would be a huge shock to the Hogwarts students and professors.
One idea could be Harley Quinn traveling back in time to meet the Joker before he became the criminal he is. She could try to change his path, which would create a whole new set of events in the Gotham underworld. Another plot could involve her traveling to the future and seeing a Gotham where she has become a hero. She then has to figure out how to make that future a reality in her own time. And perhaps she travels through different time periods in Gotham's history, interacting with different versions of Batman and his rogues gallery.
One idea could be that they are both transported to an alternate dimension. In this dimension, all the rules are different. Deadpool's healing factor doesn't work as well, and Harley Quinn's usual weapons are useless. They have to rely on each other's skills and knowledge to find a way back home. Along the way, they meet strange versions of their friends and enemies, which adds to the hilarity and confusion.
One idea could be that Deadpool and Harley Quinn team up to take on a common enemy, like a supervillain who's causing chaos in Gotham and also has a connection to one of Deadpool's foes. They could start off bickering because of their very different personalities but gradually learn to work together.