When we last left Sarah and Helena they were in a shit ton of trouble. Helena's water had broken just as they managed to incapacitate Virginia and escape the labour and delivery room. Given how long the sestras fought against Neolution, you'd think that this final confrontation would take up a large part of the episode but that's not what the writers decided to do.
PT, hopped up on medical grade meth decided to take on Sarah and try to suffocate her to death with plastic. PT managed to hold his own for a while but Sarah, being younger stronger and healthy quickly managed to kick him off of her. PT starts ranting about Sarah and Helena being his biggest mistake and the fact that no matter what Sarah does, he'll always be a part of her because he created her. PT is finally silenced when Sarah grabs an oxygen tank and smashes his brains in.
Virginia finds Helena in the basement and of course is all smug about how fitting it is for Helena to give birth in the dirt. Art walks in, relieved to find Helena, until of course Virginia gets the drop on him. Art is forced to hand over his gun. Virginia keeps her eye on the prize and demands that Art put on a pair of gloves and check to see how dilated Helena is. In the process of checking on Helena, Art notices that she has a screw driver tucked against her side to use as a weapon. Art pretends that there's something wrong with Helena and when Virginia comes to check, Art manages to disarm Virginia before pushing her in Helena's direction. Helena seizes the opportunity and uses the massive screw driver to take out Virginia.
With PT and Virginia out of the way, there's still the matter of Helena being in labour. Sarah joins Art and Helena in the basement and helps Helena with her labour. Throughout this process, Sarah keeps having flashbacks to her pregnancy. In one scene, Sarah sits outside of a women's health clinic with Siobahn, debating whether or not to terminate her pregnancy. As Helena begins to push, Sarah remembers her own labour and Siobahn holding her hand and encouraging her during her own delivery experience. Helena gives birth to two healthy boys. So much for PT's declaration that "the future is female".
The rest of the episode deals with the sestras trying to settle into life now that there are no more enemies to vanquish and their lives are finally their own. Sarah is the clone who has the biggest issues with the transition and that's hardly surprising given that even before she became aware of Neolution, she had difficulty being still or settling into any kind of routine.
Now that Siobahn is gone, Sarah is solely responsible for caring for Kira and she's clearly overwhelmed. Sarah is forced to give Kira money for lunch because once again, she's forgotten to go grocery shopping - a mundane task that Siobahn clearly always took care of. When Felix arrives, he is shocked to find a for sale sign on the front lawn. Sarah argues that they talked about this but it's clear that Felix isn't onside with giving up his family home just yet. Felix even points out that Sarah has no plan for Kira who needs stability. They don't have time to talk about it though because Sarah is going to take her GED so that she can get a job.
Once inside the school, Sarah learns that everyone in her class is at least ten years younger than her and so she walks out. When Sarah arrives at Helena's baby shower, she's clearly out of sorts and lies to everyone about taking her test. When it's brought up that the house is for sale, it's Allison who pushes for Sarah to stay put because the house represents stability of Kira, who is becoming close with Charlotte. An exasperated Sarah yells that Kira doesn't need to live in a house where her grandmother has been shot to death.
What happens when you get everything you've always wanted and there's no one left to fight? This is Sarah's problem. She's always been in the thick of things and so making an adjustment to just standing still difficult. It's the stillness that causes Sarah to think about her short comings and the mistakes that she's made. Every woman who parents worries that she is failing her child but in Sarah's case it's not just typical worry, given that she once abandoned Kira for a year. Sarah wants to run away and escape, but this time, there's no Siobahn to fall back on.
In the wake of Siobahn's death, Cosima and Allison talked about Sarah not mourning the passing of Siobahn and the fact that she's always had to be the strong one. It's not until the sestras gather alone that Sarah is able to see that while she no longer has a maternal figure, she has sestras that she can lean on. Allison reveals that she scared her child when she yelled and threatened her. Helena talks about letting her twins eat sand. Cosima talks about how afraid she was to hold Orange, Helena's son, and the fact that she doesn't have a maternal bone in her body. For Cosima, a lack of a desire to mother makes her wonder if she is cold and selfish. It's this honesty about short comings that finally allows Sarah to cry not only for Siobahn but for herself.
While all the sestra drama has been going on, Felix has been working on a surprise of his own. A car pulls up to the curb of the Hendersons and it's none other than Rachel. Rachel asks about her sestras and the health of Helena's twins. Felix makes it clear that while everyone is fine, Rachel is not welcome inside the home. An isolated Rachel, who admits that she doesn't have a single friend in the world, or even an identity because it would make her traceable, has no desire to ever see a face that looks like hers again. Rachel hands Felix a package before leaving.
Felix joins the sestras in the backyard and hands over the package he received from Rachel. Inside is a list of well over 200 Leda clones, their location, contact information and their health status. This is the information that Cosima and Delphine have been looking for. With this list, they can now ensure that all of the Ledas receive treatment. The sestras find comfort in knowing that none of the other clones will have to go through what they did. They may all be clones but the sestras are bonded by pain and shared battle.
In the end, the sestras end up with everything that they fought for. Helena is raising her beloved babies, Sarah stays in Siobahn's home with Kira and Felix and Cosima and Delphine travel the world distributing the cure to the other Leda clones. Donny and Allison have their version of marital bliss.
In the end, it's Helena who tells the story of the sestras in an journal she's titled Orphan Black. The story begins with Sarah getting off a train and seeing Beth.
More than wrapping up lose threads, this series finale is really about the sestras tending to their wounds after battle and finally having full autonomy over themselves. They may look a like but they are very different women on the same journey to finally embrace happiness and security. It looks different for each of them but that's the point - they're finally individuals in their own right.