Well, the plot could involve a strange experiment that causes Harley Quinn to become pregnant. Nightwing gets involved because he's trying to figure out what's going on. As the story progresses, they have to deal with villains who want to use the baby for their own evil purposes. They might also have to deal with their own personal issues, like Harley's past relationship with the Joker and Nightwing's loyalty to Batman.
In this fanfiction, perhaps Harley Quinn and Nightwing have a one - night stand which leads to her pregnancy. At first, they don't know how to handle it. Nightwing is worried about his reputation as a hero and Harley is scared of how the villains will react. But as time passes, they start to see the potential in their relationship. They could learn from each other, with Nightwing teaching Harley about redemption and Harley teaching Nightwing to loosen up a bit. They would then fight together against any threats to their new family.
One challenge would be acceptance from their respective communities. The heroes might not accept Nightwing being involved with Harley, a former villain. And the villains might see Harley as a traitor for being with a hero. Another challenge could be protecting the pregnancy from their enemies who might want to harm them or use the baby for their own gain.
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 possible plot could be that Harley Quinn discovers she's pregnant and tries to hide it from the Joker, fearing his reaction. Meanwhile, Batman somehow gets wind of it and feels a sense of responsibility to protect her, not just for the baby's sake but also because he realizes Harley is in a very vulnerable state.
Well, the plot could involve Harley Quinn and the Joker having an unexpected pregnancy. It could show how their relationship changes. The Joker might initially be dismissive or even angry, thinking it'll disrupt his plans. But Harley could be determined to have the baby and try to make the Joker understand the importance of family, or at least her version of it. There could also be a lot of drama with other villains or heroes reacting to the news of Harley being pregnant.
Another idea is that the father of the baby is a mystery, and Harley goes on a journey to figure out who it is. Along the way, she discovers things about herself and her past relationships. This could involve her visiting old friends or foes and reminiscing about different parts of her life.
Poison Ivy might be a candidate in some creative fanfiction interpretations. Their relationship has always been very close, and if there was some kind of magical or experimental situation, Ivy could potentially be the other parent. This would lead to a very unique family dynamic and story arc.
The Joker is an obvious choice as he has a long - standing relationship with Harley Quinn in the original lore. Their complex and often toxic relationship could add a lot of drama to the pregnancy storyline.
A plot might involve Harley Quinn getting amnesia. Batgirl finds her and decides to help her. In the process of trying to help Harley regain her memory, they form an unlikely bond. But as Harley's memory starts to come back, she remembers that she has a score to settle with some of Gotham's criminals, and Batgirl has to decide whether to support her or stop her.
Perhaps Naruto is raised in a world where both the Naruto and DC elements are combined. He grows up learning ninjutsu but also has a penchant for Harley Quinn - like pranks. His story could be about him trying to bring peace to this mixed - up world. He uses his Rasengan in new and creative ways, like adding some of Harley's acrobatic flips to his attacks. And he has to deal with villains who are also a combination of Naruto - style bad guys and DC villains.
One possible plot could be Harley Quinn causing chaos in the prison. Maybe she forms an unexpected alliance with other inmates and they plot to break out. And the 'lemon' aspect could involve a budding romantic or flirtatious relationship with a guard or another inmate, but in a more comical and Harley - Quinn - style crazy way.