On Orphan Black, the many female clones of Project Leda, all played by the brilliant Tatiana Maslany, have had their genetic code patented, their eggs harvested, their bodies sterilized, and their sexual histories interrogated. That powerful men—scientists, capitalists, or religious leaders—might want to clone human women, closely monitor them, and tamper with their reproductive systems does not take a huge imaginative leap. After all, women’s bodies have always been subject to scrutiny, study, and surveillance; state-directed forced sterilization is barely recent history. Orphan Black, entering its fourth season Thursday night on BBC America, is obviously a work of science fiction, but the way this show treats the body—the female body—is anything but unthinkable. 

After a tortuous third season that veered off track with a convoluted plot about a military-grown batch of homicidal male clones, Orphan Black has returned to its core theme of bodily autonomy. This back-to-basics approach also includes the return of season one’s primary antagonist: Neolution, a shadowy movement preaching the pseudoscientific doctrine of “self-directed evolution.” (What that means in practice, from what we’ve seen, is creepy body modification: clubbers with white contact lenses and men with tails on their backs.) Neolutionists, we learn, have infiltrated all the other secretive organizations the show has introduced. Neolution is the insidious bond now holding this cumbersome plot together. 

The choice to bring back Neolution could have come across as backtracking—the show’s writers realizing the error of their ways after a poorly received season, and returning to what worked well in season one. And in some sense, that’s what it is. As Sarah, the closest thing the show has to a clone protagonist, says in a later episode: she’s going “back to the beginning of all this shit.”

So it’s fitting that the season begins with a near episode-long flashback to Beth, a character who died in the pilot’s first moments. A cop driven mad by investigating her origins, Beth has always been the most enigmatic of the clones; her suicide kicks off the show, and we only ever knew her second-hand, through home videos and stories from the other main clones (Alison, Cosima, and Helena, who are all underutilized in the season’s first few episodes). The flashbacks—in which we learn that Beth was directed to Neolution by a new clone, M.K. (she’s paranoid and European, like a less-feral Helena)—leave us with more unanswered questions. But seeing Beth in the days leading up to her suicide, before we ever met Sarah Manning, reframes things. The flashback is engaging, with Sarah and Beth physically retracing each other’s steps, months apart, both searching for answers.

The search for answers, which often drives the action on Orphan Black, is most compelling when it bumps uncomfortably into reality. An effective scene from season two had Sarah investigating the history of Project Leda, digging through files in a church basement, pulling up records of something called the Cold River Institute. She finds old twentieth-century photographs with labels like, “Most Perfect Baby, 1908.” The inspiration for Cold River, Jill Lepore writes in the New Yorker, comes from the very real Eugenics Record Office in Cold Spring Harbor, New York. Orphan Black may take a few liberties with current science, but the show has a clear understanding of history’s darker moments and the dangerous, often ignored consequences of scientific inquiry.

Season three abandoned these quiet moments of horror for loud scenes of torture and a ricocheting plot. Orphan Black is at its best when the camera and the plot are trained on Tatiana Maslany, and all the time spent last season on the male clones, played capably by Ari Millen, felt like a waste. The show never came close to revealing why the male clones, known as Project Castor, were created. It didn’t even seem that interested in asking the question. As shadowy entities proliferated, it became hard to remember any narrative thread beyond the characters’ survival. 

In season four, Orphan Black regains the sharp feeling of curiosity that drove Sarah at the show’s start. Sarah’s choice to dig into the mess, to try and find some answers, broke the cardinal rule of the Project Leda: that the clones remain unaware. That same pursuit of answers drove Beth over the edge. For the women in Orphan Black, knowledge is dangerous. It’s also essential.