The episode 11 of "Reign" is called "Inquisition." The episode features the return of King Henry to the castle and accusing Queen Catherine of adultery and treason. In "Reign," There is only one punishment when someone is accused of these crimes -- death. And, one cannot expect the queen to quietly accept her fate, or behave like a whimpering, meek woman. Queen Catherine will come with a plan to save herself at the cost of Bash's life.
The preview clip of "Inquisition" provides a glimpse of King Henry returning to the castle. He can be seen saying that the Queen has made more enemies than just him and that it is time for her to pay. Pushed into a corner, Queen can be seen telling Mary that her only chance is to destroy Sebastian.
The spoilers of the upcoming episode reveal that she threatens to expose Bash's dark past. This might be related to his uncle being a pagan, and killed because of that. In the previous episode, Mary came to know about Bash's pagan and heretic connection.
To protect Bash and stop Queen Catherine from destroying Bash, Mary will be determined to find out a darker secret from Catherine's past. She and Bash will go on a "quest to expose an even more deadly secret from Catherine's past," according to the official synopsis of "Inquisition."
Also in the episode, Nostradamus will reveal the identity of the Castle's ghost as Clarissa. It was very much expected after Clarissa stabbed the prophecy maker, with a blunt object. This revelation is going to shock, everyone. The preview chip shows a chained Nostradamus inside a prison cell.
It looks like "Inquisition" is about Mary and Queen Catherine move to outwit the other, before one Queen crushes the other Queen.
Mike Rohl has directed the episode, while Doris Egan has written it.
There is no glimpse of Francis in this episode, as well. It is highly possible that when he returns, a mighty storm will follow him.