When communication with Cosima is cut off and Neolution appears to be within striking distance, Sarah’s alliance with Rachel goes out the window. Sarah lures a high-level Neolutionist into a trap, and sets out to bring down Neolution once and for all.
- Tatiana Maslany as Sarah Manning, Cosima Niehaus, Helena, Rachel Duncan, Krystal Goderitch, and Alison Hendrix.
- Jordan Gavaris as Felix Dawkins
- Kevin Hanchard as Arthur Bell
- Ari Millen as Ira
- Josh Vokey as Scott Smith
- Kristian Bruun as Donnie Hendrix
- Maria Doyle Kennedy as Siobhan Sadler
Special Guest Star
- Jessalyn Wanlim as Evie Cho
- Lauren Hammersley as Adele
- Rosemary Dunsmore as Susan Duncan
- Cynthia Galant as Charlotte Bowles
- James Frain as Ferdinand Chevalier
- Gord Rand as Detective Martin Duko
- Scott Wentworth as Dr. Ian Van Lier
- Lucie Guest as Zoie
- Calwyn Shurgold as Hell Wizard
- Géza Kovács as The Messenger
- Frank Moore as Board Member #1
- Andrea Davis as Board Member #2
- David Christo as Reporter #2
Sneak Peaks and Promos
- For her "camp" look, Evelyne Brochu went almost completely without makeup for Episodes 4.09: The Mitigation of Competition and 4.10: From Dancing Mice to Psychopaths. Producers also thought it was time to bring back some of her infamous curls, for practical and realistic reasons and for the Cophine fans.