Sarah fights for her life on the Island and tries to stay strong enough to rescue Cosima; Cosima and Delphine reunite.
Rachel gives Sarah an ultimatum, and her decision causes a clash with Kira; Felix brings an old ally into the mix.
Alison seeks to return to her community center, but Bailey Downs has moved on; the ghost of friendships past haunt.
Mrs. S. and Sarah set out to investigate a lead on a Neolution defector; an unexpected reunion takes place; Cosima has a terrible discovery.
Sarah and Kira spend time at home; secrets are unlocked about Kira's gifts; Cosima joins Delphine at the mansion.
Cosima is forced into an alliance that accelerates PT Westmorland's agenda; Krystal stumbles onto a vital clue.
Westmoreland demands a more aggressive action on Kira; Sarah fights to save her daughter; Rachel discovers a dark secret; Cosima has a clue about Westmoreland's identity.
Mrs. S orders the sisters to celebrate Felix's art opening; Sarah remains on edge with a nagging suspicion that S is hiding something.
A devastating loss is suffered; Sarah learns that Helena has been kidnapped; Clone Club bands together to find Helena before her babies are born.
Helena takes shelter behind enemy lines, and Sarah and Art struggle to protect her and end the siege.