Sarah pursues Helena, who is being held in a compound far away; Sarah must deter a Topside investigator.
Castor pursues the clones in order to obtain original tissue samples; Helena is examined by a new villain.
Leda and Castor hunt for the original clone DNA; Mark and Gracie pursue new leads; Art and Sarah reunite.
Rachel bargains for her freedom with decoding Duncan's Moreau book; Sarah must pursue the Original Castor.
Helena works in a faraway military compound; Sarah's fate hangs in the balance as she tries to save her sister.
