![Orphan Black Season 3 Episode 4 Orphan Black Season 3 Episode 4](http://images.weserv.nl/?url=//image.tmdb.org/t/p/w185/vL6jsqTONNsvqdkIKPFfSJGrPCc.jpg)
Orphan Black Season 3 Episode 4
Mark is taken down in a Prolethean shoot-out and Sarah must step in to help. But as Sarah gathers intel that puts her on the trail of the original Castor DNA, a familiar foe is not far behind. While Helena continues to toil in a faraway military compound, it is ultimately Sarah