One plot idea could be a team - up where they face a new, extremely powerful villain that neither of them can defeat alone. This villain could have powers that are a combination of their weaknesses, like a being that can manipulate kryptonite and also has the strategic mind of Batman's enemies. They would have to learn to work together in a new way.
Another plot could be a story where their identities are all exposed at once. They have to deal with the public's reaction, which could be a mix of fear and adoration. They then have to work together to protect their loved ones and also find out who is behind the identity leak. This would explore their personal lives as well as their superhero personas.
A time - travel plot could be really interesting. Maybe Wonder Woman gets sent back in time to the early days of Superman's arrival on Earth. She has to team up with a young Batman to help Superman figure out his place in the world while also dealing with the changes they make to the timeline. It could explore how their relationships might have been different in the past.
One plot idea could be that an otherworldly threat emerges that only their combined powers can stop. They have to put aside their differences and work together seamlessly. For example, a powerful alien race plans to invade Earth and they need to use Batman's strategic mind, Superman's super strength and Wonder Woman's combat skills.
A good plot could be that the world is suddenly hit by a wave of anti - superhero sentiment. Wonder Woman and Superman are two of the main targets. They have to go undercover and live among the humans for a while. During this time, they learn more about the regular people's fears and concerns. They also start to develop a romantic relationship as they rely on each other for support in this difficult situation.
One idea could be that Superman and Wonder Woman have to team up to stop an ancient alien threat that is immune to their individual powers. They must combine their strength, speed, and wisdom to find a way to defeat it.
Maybe in the fanfiction, Superman and Wonder Woman get married in a secret ceremony. Then they have to deal with the reactions of their superhero friends and the public. Some are happy, while others are worried about the implications of their union on the superhero community.
One idea could be that a powerful new villain emerges who is a threat to both Gotham and Themyscira. Batman and Wonder Woman team up to track down the villain's lair. Batman uses his detective skills to analyze the clues while Wonder Woman uses her combat skills in the battles along the way.
One idea could be that Batman and Wonder Woman have a child who inherits their combined skills. The child might struggle with the high expectations and the different worlds of Gotham and Themyscira. Another plot could be about them forming a family unit to protect the world in a new way, using both Batman's detective skills and Wonder Woman's warrior abilities.
One idea could be that Batman and Wonder Woman have a major disagreement over how to deal with the Injustice regime. Batman wants to use more stealth and subterfuge while Wonder Woman believes in a more direct approach. This could lead to some intense battles between them, not physical but more of a battle of wits and ideologies.
One plot idea could be Batman trying to convince Wonder Woman to see the error of her ways in the Injustice universe. Maybe he shows her the long - term consequences of their actions on the common people. Another could be a story where Wonder Woman and Batman have to team up against a greater threat that makes them re - evaluate their stances in the Injustice conflict.
One idea could be that Batman and Wonder Woman are both vying for the attention of a new superhero in town. Batman is jealous because Wonder Woman seems to have a natural connection with this new hero, perhaps due to their similar powers or backgrounds. Wonder Woman, on the other hand, is jealous of Batman's detective skills which the new hero seems to admire a great deal. This could lead to a series of challenges and competitions between Batman and Wonder Woman to prove who is more worthy of the new hero's friendship or alliance.
A possible plot is that a powerful magical object has been stolen by a group of rogue Lemmins. Batman and Wonder Woman get involved as this object has the potential to cause chaos in the entire DC universe. They journey to the Lemmin homeland, which is a beautiful but dangerous place filled with floating islands and strange energy fields. As they search for the object, they learn more about the Lemmin society, their social hierarchies, and their unique forms of magic.