In Orphan Black's riveting season finale, even family can't be trustedOrphan Black had real challenge for its season finale. It had to make some major revelations in a show that's all about major revelations, while stepping up the stakes for our core clones. And it delivered, with a mix of violence and intrigue, and by the end, nearly all the clones have blood on their hands. Spoilers ahead.

Well, if Orphan Black didn't engender some good old-fashioned paranoia before, it certainly will now. Let's start with the Neolutionists. After Art arrests Sarah, she's dangerously close to spilling the beans about the whole clone thing. Despite her conning of Art, Sarah clearly trusts him—and perhaps feels a bit of guilt about deceiving him. But before she can bring herself to confess her clonehood, an attorney—her attorney—busts into the room and hauls her off to the Dyad Institute offices.

In Orphan Black's riveting season finale, even family can't be trusted

There we meet the mysterious woman from last week, and she is indeed a clone, a professional clone, it seems. Rachel makes Sarah an offer: mutual disclosure and "protection" for Sarah and Kira. Sarah just has to sign a little contract and tell the Institute everything she knows. Meanwhile, Leekie makes a similar offer to Alison. He's removed her monitor (he claims), but wants her to submit to regular medical tests. As for Cosima, she's offered a cushy job at the Dyad institute studying the clones. Leekie hands over her sequenced genome as a peace offering. Alison is tempted to take the offer. Sarah is worried there might be no other choice.

They really broke the budget on this episode, by the way. It's rare that we see the clones' faces together in the same frame, but in Felix's studio, we get Alison, Sarah, and Cosima, who has flown into town, sitting around and discussing their options. Cosima and Sarah have made up thanks to Cosima's heartbreak.

In Orphan Black's riveting season finale, even family can't be trusted

Delphine blows into town, too, and after receiving less than her fair share of Felix's snark, convinces Cosima that she really does want to help her. They get to work trying to decode the synthetic "bar code" sequence in Cosima's DNA based on her tag number, which Delphine knows by heart. That last bit is weirdly romantic.

Cosima has a problem, though, one that makes that Dyad offer a tad more tempting: she's sick. Like Katja, she's started coughing up blood, suggesting that she may share her fellow clone's respiratory ailment.

In Orphan Black's riveting season finale, even family can't be trusted

Art and Angie continue their investigation of Sarah through one of her known associates: Vic. Vic's actually working a rehab program. It seems that losing his fingers and getting stabbed in the hand with a nail gun is Vic's version of rock bottom. Good for him. He directs them to Alison (whom he still thinks is Sarah), but Art and Angie immediately realize that Alison isn't Sarah at all but another identical woman. You're almost there, guys.

Alison notices awful Aynesley is moving away, and of course assumes that this is the monitor removal. She follows Aynesley inside, passive-aggressively trying to get her to confess to being her monitor. But Aynesley's just pissed; she gets her best prime-time soap opera moment when she pulls a felt angel Alison made her from a box and says, in a scary hushed voice, "To hell with you and your Christmas angel." But when she tries to force the angel down the disposal, her scarf gets caught and starts to strangle her. Alison rushes to turn off the disposal, but at the last second, her fingers hover over the switch. Granted, Alison smacked her husband in the face with a golf club and then tortured him in the craft room, by my jaw dropped when she let Aynesley die in that freshly renovated kitchen. Lady has gone dark.

In Orphan Black's riveting season finale, even family can't be trusted

Oh, but here's the kicker: Aynesley wasn't her monitor. Dr. Leekie is lying liar and he lied to Alison about removing her monitor. That's because her monitor is Donnie. We all knew Donnie was up to something and it turns out that yes, he has been her monitor all this time. I wonder, has he been watching her since they were kids? Or is that why they got back together in college?

But the biggest bombshells are reserved for Sarah. Forget that the Dyad Institute knows about Kira. Forget that Helena is her shared-a-womb twin sister. Amelia has an even bigger shock in store for Sarah: Mrs. S was one of the scientists who contracted Amelia as a surrogate. Amelia accidentally tries to deliver the news to the wrong twin, however, and is stabbed by Helena for her troubles. Helena's motive seems to be bitterness over her terrible childhood. "You gave me to them," she croaks in her sleepy, disaffected way. "You let them make me this way."

In Orphan Black's riveting season finale, even family can't be trusted

Sarah discovers Amelia just before she dies, and Amelia hands her a photo of a woman and a man in lab coats. (The woman is not Tatiana Maslany.) "Your foster mother," Amelia tells her. On the back, the names of the people are blacked out, but one name isn't: Project Leda.

In Orphan Black's riveting season finale, even family can't be trusted

Brief mythological time-out: Leda is a figure from Greek mythology who was impregnated by Zeus, who was in the guise of a swan. She gave birth to two eggs. From one egg hatched Helen (later of Troy) and Pollux, who were fathered by Zeus and therefore semi-divine. From the other hatched Clytemnestra and Castor, fathered by Leda's mortal husband Tyndareus. We generally remember Castor and Pollux as being the famous twins; when Castor died, the immortal Pollux asked Zeus if they could share his immortality with his brother and so Zeus placed them in the stars as the constellation Gemini. Project Leda could refer to all the clones (with swan conception as a metaphor for in vitro fertilization), but it likely refers to Sarah and Helena specifically. Twins, one with divine powers.

Sarah is distraught that Helena killed the closest thing they had to a biological mother, and although Helena still refuses to kill Sarah, Sarah doesn't feel the same way. She pulls out a gun. "Together, we make a family," Helena protests. "I have a family," Sarah tells her (perhaps realizing it herself for the first time) and shoots. Helena gets a few notes of death music, but I can't help but wonder if we haven't seen the end of her.

In Orphan Black's riveting season finale, even family can't be trusted

Delphine and Cosima eventually crack the code and find the information contained in the synthetic sequence. It's an intellectual property notice! Dyad has patented the clones' genomes and included this notice, stamped on each one's DNA: "This Organism and Derivative Genetic Material is Restricted Intellectual Property." Derivative genetic material—that would be Kira. Dyad is claiming ownership of the clones and their issue.

Between this revelation and a pep talk from Paul (who is still nominally working for Dyad), Sarah decides not to submit to Dyad, instead sending Rachel an articulately worded email:

In Orphan Black's riveting season finale, even family can't be trusted

Rachel simply calls someone up on her phone and tells them, "You know what to do." Sarah returns to Mrs. S' to find the place ransacked and Mrs. S and Kira both missing. This season began with Sarah trying to get Kira back and ended with Kira slipping through her fingers.

Well, thank you, folks at Orphan Black, BBC America, and Tatiana Maslany for a thrilling ten episodes of television. It will be a while before we revisit Sarah, Cosima, and Alison, but it's never too early for speculation. Is Helena really dead? Is Mrs. S still in league with the Dyad Institute, or was she trying to hide Sarah from the cloners? If the clones' genome is patented, does that rule out an "original"? Is Cosima doomed? And will Vic ever figure out what on Earth is going on? And is the identity of Kira's father important in all this?

I'm going to miss talking about the show with you all week after week. Until next season!