I just finished Orphan Black and you should watch it, too. Am I a little behind the times? Sure, but that's what the library is for; catching up on shows you may have missed on TV. If you like dark and very twisty shows, Orphan Black is for you.
I won't share too much because I don't want to give away any of the twists, but the show opens with Sarah, a woman who has made some poor choices in life. She has a child, but doesn't feel qualified to properly care for and has fallen in with the 'wrong crowd'. She's on a train platform when she witnesses a woman commit suicide, which is awful, but even worse, the woman looks just like her! Sarah is lost and confused and we as the audience have no more information than she does, so we are just as lost and confused. It's great and intriguing and pulls you straight in. And that's all just in the first episode. There's science and it all rides the edge of possible without being too hard to follow. I love pretty much the whole cast of characters and even the villains feel like real, if incredibly misguided, people.
It's a BBC Canada show, so seasons are only 10 episodes long and there were 5 thrilling seasons. They continued the show in a podcast and recently it's been announced that there will be a spin-off show. Tatiana Maslany stars in Orphan Black and you may recognize her as the new She-Hulk. This show is just so good, I cannot recommend it enough.
If you've already watched Orphan Black and are looking for some more twisty shows, here are some more options: