Alexis Thinks Beckett is Cheating Fanfic: How Will Alexis React?

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.

In the fanfic, it could be that there are signs that Beckett is hiding something. Perhaps he has unexplained absences. He might say he's at work but Alexis can't reach him during those times. Also, he could be overly protective of his phone or personal space, which makes Alexis suspect that he's cheating.

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.

Well, without having read the actual 'beckett and alexis killed fanfic', it's difficult to give a detailed account. However, generally speaking, it might be a piece of fan - made fiction that focuses on a plot where Beckett and Alexis are somehow related to a killing. Maybe they are the ones who do the killing, or perhaps they are witnesses or victims in a more complex scenario.

A common theme is friendship. Many fanfics explore how Beckett and Alexis become friends and the bond they share. Another theme is growth, as they both develop as characters within the fan - created stories.

He could also gather evidence of Alexis' attempts to hurt him. If it comes to it, he can use this evidence to expose her actions to those around them, like mutual friends or authorities in their fictional world. Another way is for Beckett to strengthen his own defenses, both physically if it's a more action - oriented fanfic, and mentally by not letting Alexis' actions get to him.

She is probably angry and frustrated. She would demand Castle to explain why he thinks so and would be hurt that he doesn't trust her.

Alexis could also try to engage in discussions with other fans of Beckett. By sharing her/his views, Alexis might gain new perspectives and either change her/his mind about fanfic in general or at least find a subset of fanfic that she/he can tolerate.

It could be that Castle is overprotective. He loves Alexis so much that even the slightest sign of Beckett not being on the same page as Alexis in Castle's eyes makes him think Beckett hurt her. Maybe Beckett gave Alexis some career advice that Castle thought was too pushy.