On Wallach IX, young Valya Harkonnen promises Mother Superior Raquella that she'll protect the Sisterhood by putting one of their own on the Imperial Throne. Thirty years later, Valya faces a threat to her long-awaited plan.

After receiving word about events on Salusa Secundus, Valya brings Theodosia to the Imperial House to help manage the situation. Meanwhile, a reluctant Tula enlists Lila for a vital mission.

Following a tragedy, young Tula worries about being accepted despite her family name, while a skeptical Valya struggles with the decision to take the Sisterhood vow. Years later, Valya receives a message that confirms her suspicions.

After nearly all the acolytes have the same nightmare, Tula attempts to understand the origins of their disturbing dreams. Meanwhile, on the eve of the great Landsraad meeting, Valya sets her plan in motion to redeem House Harkonnen, Ynez confronts her father about rumors surrounding Desmond, and Kieran conspires to advance a rebel attack that the Sisterhood must try to thwart.

As Corrino names a new Bashar, a Sister with deep connections to the Emperor arrives on Salusa Secundus... sending ripples through the Royal House. After receiving a tip, Desmond goes on a warpath to root out the insurgents. Meanwhile, Tula tries to keep her secret project from being discovered by the other Sisters.

As Tula contends with the stunning reveal of Desmond's true identity, the acolytes uncover a devastating long-held secret about the Sisterhood. Meanwhile, Valya executes her plan for Ynez's escape... which leads to an epic confrontation with an increasingly powerful Desmond.