A discussion on Jonathan Haidt's "The Righteous Mind".
To prepare I would strongly advise reading the book because the discussion will take the form of the different parts of the book, those being:
Part I Intuitions Come First, Strategic Reasoning Second
Part II There’s More to Morality than Harm and Fairness
Part III Morality Binds and Blinds
However, there are plenty of resources out there, a good place to start are the discussions on the book that can be found here:
Please find the final chapter of the book here, it will give you a good idea of the central ideas: https://docs.google.com/document/d/1vBZTAcJ7_O2jdUaJOqLQCQEHW_MBgFCAa0AoW2j7Gpw/edit?usp=sharing