Tension mounts in the penultimate episode of Dune: Prophecy as Mother Superior Valya (Emily Watson) introduces another trump card in the form of Sister Francesca — enter Tabu — in her struggle to wrest power back for the Bene Gesserit.

Desmond Hart’s (Travis Fimmel) war against insurgents gets positive affirmation as he is promoted to the post of Bashar, the leader of an elite Imperial guard that is tasked with rooting out insurgents. But even as he embarks on his personal quest of linking insurgence to the Sisterhood, Valya finds yet another way to introduce a Sister into the royal court to curry favour.

Tabu’s introduction as Sister Francesca — concubine to Emperor Javicco (Mark Strong) and the mother of Constantine (Josh Huston) — to the royal court is exactly the trump card needed to manipulate proceedings after the Sisters were thrown out of it. Javicco, who seems to be swayed by whoever is speaking to him at that moment, continues to be infatuated with Francesca and is clearly putty in her hands as she manipulates him into giving their son some more responsibility. Tabu plays Francesca with grace and calm confidence, slipping with ease from seriousness to coquetry to emotionally manipulative to stoic.

When Constantine exposes Kieran Atreidis (Chris Mason), the Swordmaster, as the traitor in the royal court, Javicco gives into Francesca’s manipulation and appoints Constantine as the commander of the Imperial fleet. But will Constantine remain under the control of his mother for the Sisterhood to be able to use his position to their advantage? The evidence we get in the episode doesn’t really bode well. Not only is Constantine questioning Francesca leaving him behind with a father who doesn’t like him and understanding that even his birth has a purpose for the Sisterhood, the other example of a Sister sacrificing a child for the cause of the Sisterhood has clearly come back to wipe them from existence.

We refer to the big reveal of Desmond Hart being the son of Sister Tula (Olivia Williams) and Orry Atreidis, abandoned to survive on his own, and the fact that he is using a version of the Omnius plague to kill his victims. His mission gets the support of Empress Natalya (Jodhi May), whose plans for power are thwarted by Sister Francesca.

With only one episode to go, we still don’t know how these two people — Francesca’s son Constantine and Tula’s son Desmond — will influence the balance of power. We are also left with more questions than answers and we wonder how all of it will tie together in next week’s episode.