With Helena forced to take shelter behind enemy lines, it's a bloody last stand for survival as Sarah and Art struggle to protect her, and end the siege on the sestras once and for all.

Cast: Tatiana Maslany, Jordan Gavaris, Kevin Hanchard, Kristian Bruun, Ari Millen, Josh Vokey, Maria Doyle Kennedy, Evelyne Brochu, Skyler Wexler, Stephen McHattie, Kyra Harper, Lauren Hammersley, Elyse Levesque, Cynthia Galant, Nicholas Rose