Following the destruction of the recently built Blue and Human cooperative research facility, Kiani finds herself back in Marielle, the underwater city she once naively called home, to establish a new base of operations for her team. Meanwhile, tensions between the Elite Council led by Siphon and Saba's commander Thallassar have reached a boiling point as Saba's citizens begin to flee the war-torn city to join Kiani's cause, leaving Saba's leader grasping for control. And when Thalassar decides to take matters into his own hands, Kiani is forced to make a difficult choice of whether or not to battle her former soldier in arms, and seal her confirmation as an enemy of the state!