I'm writing a crossover fic between two of my top fandoms, featuring characters I adore from those fandoms and have never really had a problem writing on their own.

I try to bring them together and they just will not talk to each other!

Gah!

I've always thought dialogue was one of the weaker points of my writing anyway, but these guys? They need to talk, right now, things need to be said. But they won't bloody well cooperate!