The cartoons by Charles Addams in The Addams Family feature a unique blend of horror and comedy. The art style is distinct, with detailed and sometimes creepy illustrations. Also, the family dynamics are portrayed in a way that's both unconventional and fascinating.
Alexis might confront Beckett directly. She could say something like 'I think you're cheating on me. What's going on?' This is a very straightforward approach.
I don't know who Alexis is in this story without reading it. But it's likely that Alexis is either the main character or an important figure in the events that unfold in the 'creepy subway' setting.
A lawyer could be an important character. This lawyer takes on Alexis's case, believing in their innocence. The lawyer has to battle a corrupt legal system or powerful opponents who want to see Alexis locked up for good. The fanfic could show the lawyer's strategies and how they build a case in Alexis's favor.
Perhaps there have been some rumors or whispers in their fictional world that have reached Alexis' ears. Even if they are baseless, they can plant the seed of doubt in Alexis' mind, making her think that Kate is cheating.
She could be defensive of Beckett. Since Alexis probably has a good relationship with Beckett, she may try to convince Castle that he's wrong and that Beckett didn't mean any harm. For example, she might tell Castle about all the positive things Beckett has done for her.
Kate might get defensive right away. She could say things like 'How could you think that of me?' and be angry at Alexis for not trusting her. This is a common reaction when someone is wrongly accused in a fanfic or in real life.
The Addams Family could fit into Gotham's universe in many ways. For example, they could be seen as an eccentric family living on the outskirts of Gotham. Their macabre interests and strange behavior might be misinterpreted by the citizens of Gotham as something more sinister. Gomez could interact with some of Gotham's mobsters in a very unique way, perhaps out - of - the - box business deals. Morticia's elegance and mystery would add a different kind of charm to the dark city. And Wednesday, with her penchant for the morbid, could find Gotham a rather interesting place to explore, especially with all the dark alleys and strange characters.