If you have never seen Becket, the movie, with Peter O'Toole and Richard Burton, you must. It's based on this play by Jean Anouilh that I had never read. I ran across the LA Theaterworks production on Audible and gave it a try. Wonderful production and play. My only complaint is that it was sometimes difficult to distinguish the voices to determine who was speaking. If you can, get a copy of the printed play to read along with the audio.
I won't bother with any kind of plot summary. Everyone knows (or should know) the story of Henry II and his stormy relationship with Thomas Becket. It has ethnic and religious conflict; dispute that remain unsettled to this day.
Another great movie related to Henry II is Lion in Winter, also with Peter O'Toole. Get both of them. You will not be disappointed.