Plot summary
After Siobhan's funeral, the sisters learn Helena has been kidnapped and that Neolution is trying to force the immediate birth of her twins. Westmorland's backers have started to be murdered but Felix and Art are able to get information with Rachel's help. They are hiding Helena in the abandoned asylum wing next to Dyad's main building, which is swarming with police and media with Neolution exposed. Sarah, disguised as Rachel, is taken there by Detective Engers. However, Sarah is caught before she can kill Westmorland/Mathieson. Meanwhile, Coady follows orders and euthanizes Mark, ending the Castors. Helena slits her wrist to die so her babies won't be abused like she was, but she is saved with Sarah's blood. Scott and Hell-Wizard sneak into Dyad to let Art inside the old wing. Helena bashes Coady's head against the gurney, and before she and Sarah can escape, her water breaks.
Credits
Adapted from Wikipedia contributors, List of Orphan Black episodes. HTML formatting and reference markers removed.