Prophecy centers entirely around the origins of the Bene Gesserit, known only as "the Sisterhood" in the show. However, there's a very simple reason for that. "The Sisterhood at its inception is not called the Bene Gesserit,

Prophecy, the Bene Gesserit organization is under the leadership of Mother Superior Valya Harkonnen (Emily Watson), its second leader, following the passing of Raquella Berto-Anirul. Valya is a conflicted individual - she is loyal to the Sisterhood but still feels some tie to her exiled and disgraced family.

Emily Watson, Olivia Williams and Mark Strong star in a visually grand six-part series, which takes place before the events of Denis Villeneuve’s blockbusters and focuses on a scheming drama surrounding the Bene Gesserit.