The penultimate episode of Orphan Black’s third season is a good and bloody one, primarily focusing on mothers and intimate relationships as S., Sarah and Felix head back home to London to pursue the Castor original. What they find offers yet another shocking twist, even if we’ve grown accustomed to the prevalence of twists that end pretty much every episode.

Helena is settling into suburban life nicely, dedicating herself to a “new path,” one without violence to prepare her for motherhood. But that whole “new path” thing is quickly dismissed when she sees Donny’s beaten face and finds out that the drug dealers have absconded with her frozen babies. Donny and Alison’s suburban life has only grown wackier with Helena around, but at least this week seems to begin bringing this plot to a conclusion. Plus, we get to see Helena unleash her violent fury on a room full of baddies.

But let’s get into the meat of the episode: S. reunites with her old crew in London, including Jamie, a friend who is now under the watchful eye of the sinister Ferdinand. Jamie recognizes the letter and number combo deciphered by Rachel as a prisoner ID number, but before he can let S. know about it, Ferdinand beats him to death in just one of tonight’s more unpleasant scenes.

To help distract from all the violence and grotesquery, we learn that S. was once in a band, and then this happens:

While Sarah is away in London, Cosima begins to suspect that Shay isn’t who she appears to be — this is further encouraged by Delphine’s dossier on Cosima’s girlfriend, which reveals her to be a soldier in the military. This is one of the longer games Orphan Black has played nicely since Cosima and Shay first met. That brief scene of someone snapping spy photos of the two of them pays off to unnerving effect here. Just as Leda has learned not to trust outsiders, so have we, making Shay a suspicious character no matter how much zen she preaches. Actually, the zen stuff makes her even more suspicious.

Cosima goes to Delphine with her tail between her legs and Delphine sets off to “take care of it,” which translates to staging Shay’s suicide — there is something so chilling in the way Delphine describes her old college dorm mate, who should have cut the veins in the tops of her feet if she wanted to commit suicide properly. And even though Gracie reveals that she was the Leda mole all along and Cosima relays this message (smartly sans the Gracie part), there’s a moment when Delphine pauses to silently consider this information. Will she kill Shay because she knows too much now, or out of pure jealousy and spite? Just how much has Delphine’s new role at DYAD changed her?

But the biggest, most effective sequence this week involves the tracking of the Castor original, whom Sarah discovers is an elderly former prison inmate. This scene is played to great suspenseful effect, as Sarah silently lurks through the house, gun drawn and ready to exterminate the only thing that could save the remaining Castor boys.

What she discovers is something far more crazy than she — or we — ever could have imagined: the Castor original is Siobhan’s mother, who was sent to prison for killing her daughter’s husband. Johanssen tested inmates in search of the perfect donor, and because S.’s mother absorbed a male twin in the womb (could this seriously get any more NUTS), she was the ideal candidate.

We put the pieces together even before Sarah does: not only is S.’s mother the Castor original, but she’s the Leda original, too, making her both the key to destruction and salvation in equal measure. As the original donor, she contains a unification that represents the duality of not just man or woman, but of all humanity, neatly tying Season 3's gender exploration together quite nicely in one very unpleasant package.

This reveal did seem a bit easy to guess throughout the season, particularly once we learned that Castor and Leda are siblings — they had to share a donor, no question. It’s just surprising that Cosima wasn’t the one to figure this out first.

Additional Thoughts:

  • Ugh, I know we shouldn’t like it, but I kind of love Delphine as a slippery character this season. What are her intentions now, really? She’s grown so cold, but in a very graceful way that reminds me of the kinds of characters Gillian Anderson and Kristin Scott Thomas are great at playing.
  • Gracie and Mark forever! She may have betrayed Leda, but I’m happy to see these two crazy kids back together, even if they’re getting way over their heads again.
  • This season takes the easy way out of the Alison and Donny Breaking Bad shenanigans: Helena kills everyone, takes all the money, and gives it to Alison and Donny, so they’re all set and free of drug dealing forever. Hopefully. Oh god please do not let this continue next season.