"Spartacus: House of Ashur" explores a "what if" scenario in which Ashur (Nick E. Tarabay) survives the events of Vengeance and is rewarded with the gladiator school he once served. The series follows his rise to power as a "Dominus" in the brutal world of Roman gladiators, a path he takes with the help of a fierce gladiatrix named Achillia.