The Pretender - S3.E10

Taking up with a 12 year old French princess, King John has annulled his marriage to Queen Hadwisa, who vows revenge against her former husband and the new queen, Isabella. Her plan is to have Isabella murdered while on a pilgrimage and make it appear to have been done by Robin Hood. Hadwisa's family believe they have enough support among the barons to depose King John and replace him with a new young man who claims to be Arthur of Brittany, John's nephew. While Arthur infiltrates the outlaw band, Gisburne becomes involved in the plot. Gisburne is only too eager to advance his position and finish off Robin Hood all at the same time. The Sheriff, however knows that "if Queen Isabella dies, we shall ALL hang," but gravely ill from a dog bite, he is unable to stop Gisburne.