I've got a meeting coming up with two shady co-workers, how can I prepare?

I have a meeting coming up with two shady characters. One is lying about me behind my back at work (blaming problems/project delays on me as a scapegoat) and the other is doing crafty things behind my back to get co-workers on her side and acts like she wants my job. I have to work with them on an upcoming project, how do I keep the peace without ending up in pieces?