Orphan Black - Season 4 (2016)

While Cosima examines Leekie's body, Felix and Donnie pose as a couple to learn more about a fertility clinic. Sarah discovers M.K. has her own agenda.

A risky cover mission at Brightborn yields several big surprises. The rift between Sarah and Felix grows as she checks up on Adele.

Seeing that it is the best overall solution yet not perfect by any means, Sarah and Cosima decide with Kendall's OK to set up an agreement with Susan Duncan, which they will not divulge to Mrs. S. until everything is arranged as they know she won't like what they've done. That agreement is an agent representing Susan will remove the bot from Sarah's cheek, with Cosima on site to ensure Sarah's safety. As Scott and Cosima have not yet come up with a "cure" for Cosima and the other affected Leda clones, they in turn will provide their research and Kendall to Susan, with...

Sarah regresses to old habits while struggling to cope with the consequences of her decisions - reconnecting with Beth on a dark night of the soul. Back at the lab, Cosima, haunted by vicious memories and news of Delphine, attempts a dangerous Hail Mary to find a cure. At the Hendrixes, Alison is more determined than ever to create normalcy for her kids. As she forges ahead with a birthday party, Donnie is caught in the Neolution crosshairs.

Siobhan wants vengeance for her mother. Cosima and Susan Duncan try to come together to try to finally find the cure. Neolution continues with their threats causing Alison to be terrified, and Mrs. To question her loyalty to her sestras.

The formal alliance between the sisters on one side Susan/Rachel/Ira on the other side begins in earnest. Cosima has arrived on the island where she and Susan will begin the process of finding a cure for both Leda and Castor by developing original DNA in the absence of Kendall through fertilization of one of Sarah's eggs with Ira's sperm, while Sarah and Felix meet with Rachel and Ira to discuss the next step in bringing down Evie Cho and restoring Susan as the head of Neolution. As Evie ramps up her media campaign to bring BrightBorn's work to the masses, Sarah, ...

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.