Nightsisters ( episode ) " Nightsisters " is the twelfth episode of the ' . It aired on January 7 , 2011 . Official description . " " Troubled by Asajj Ventress ' growing prowess with the dark side of the Force , Darth Sidious commands Count Dooku to eliminate her . But Ventress survives Dooku ' s assassin ation attempt , and the jilted former apprentice vows to take revenge , enlisting the aid of her kinswomen - - the mystical Nightsisters - - in her sinister scheme . " " Mother Talzin , leader of the Nightsisters , veils Asajj and her fellow assassin s in a cloak of invisibility , and they infiltrate Dooku ' s palace on Serenno . Though they fail to kill the Count , their use of captured Jedi lightsaber s leads Dooku to mistakenly believe that the Jedi have tried to kill him . Interested in protection , he requests a new apprentice from Mother Talzin . " " Plot summary . Asajj Ventress leads a space battle against Republic forces commanded by Anakin Skywalker and Obi - Wan Kenobi in the Sullust system . Ventress singles out Kenobi and attacks him , damaging his fighter , whereupon she is in turn disabled by Skywalker . Both combatants crash in the hangar of the Separatist flagship . Meanwhile , however , a conspiracy is brooding against Ventress ' life . Darth Sidious confers with Count Dooku , expressing his concerns about Ventress ' growing power , and orders his disciple to destroy her before she becomes too strong to handle , and Dooku , under the will of his master , is forced to obey . When Ventress calls him for assistance , he abandons her for her supposed failure . Shaken and infuriated , Ventress viciously engages Anakin and Obi - Wan in lightsaber combat . The confrontation interrupted by Dooku ' s order to have the flagship bombarded by the other Conferedate ships to ensure her destruction ; the combatants barely escape with their lives . Ventress is left floating in space in her nearly destroyed fighter until she is recovered by a scavenging crew , who intend to ransom her to her employers . Instead , they are all killed by Ventress , who commandeers their vessel and proceeds to the location of her old order , the Nightsisters , where Clan Mother Talzin has her tended to . In her feverish dreams , Ventress recalls how she was rescued from a slaver whom her mother sold her to and taken in by Jedi Knight Ky Narec as a child , her apprenticeship under him , his death and her descent into the dark Side , her being taken in by Dooku and his betrayal . Upon awakening , she swears an oath of revenge against her former master ; Mother Talzin puts two of her finest warriors , Naa ' leth and Karis , to assist her and provides her with the means of approaching and combating Dooku with the help of mystical invisibility potions and poisons . The three Nightsisters travel and penetrate Dooku ' s palace on Serenno , where they catch him asleep . His senses dulled by Ventress ' poison dart and the cloak of invisibility which surrounds his attackers , Dooku is caught at a disadvantage but fights back furiously , thinking his assassins are Jedi since Mother Talzin has armed Ventress ' team with lightsaber s . Nearly beaten , Dooku , who fakes being completely drained of energy , instead channels all of his rage , and , in one extremely powerful blast of Force lightning , he evicts them from his palace and disrupts their invisibility . Mother Talzin is content , however : With this attempt on his life , she reckons that Dooku will now be more anxious to get himself a new assassin and bodyguard to protect him . She contacts the Count and suggests a replacement — a male Zabrak warrior from her people — an offer Dooku decides to accept .