The December 3 episode of Supernatural is called "Holy Terror" and The CW has issued an official synopsis to describe it.
Here it is:
AN ANGEL WAR BEGINS --- After a massive angel slaughter occurs, Sam (Jared Padalecki) and Dean (Jensen Ackles) arrive at the scene to investigate and are surprised to run into Castiel (Misha Collins). While investigating, Castiel is captured and tortured. Meanwhile, Dean questions Ezekiel's demands and wonders if it might be time to tell Sam the truth. Thomas J. Wright directed the episode written by Eugenie Ross-Leming & Brad Buckner (909).
Trivia: Eugenie Ross-Leming and Brad Buckner worked for a production shingle called "December 3rd Productions" in the Lois & Clark days. Appropriate air date there, eh?