This project is unmaintained, but feel free to fork it.
It’s a conversation framework for Unity that features support for multiple actors, game events, flags and a node based editor. I am developing this in tandem with my Deus Ex-based game project The Vongott Chronicles
This is very handy if you're looking to make an RPG and don't want to code the backend for the conversation system from scratch. This plugin lets you worry about the UI and scene behaviour exclusively by sending all important events as a message to an event handler object that you define yourself.
In the wiki
MIT