In its second season, "Orphan Black" came perilously close to collapsing under the weight of its many interlocking conspiracies. The BBC America sci-fi drama still had Tatiana Maslany's remarkable performance(s) as a series of clones on the run from their makers, and it had turned each clone into a fully-realized character, many of whom could potentially carry their own show without the others. But the mythology got so dense, and forced so many abrupt changes in loyalty among both the clones and their various enemies and allies, that at a certain point I resolved to just pay attention to the character work, the comedy, and the episode-by-episode thriller material and not focus much brainpower on trying to keep track of who's in charge and what their agenda is.

The third season, which premieres Saturday night at 9, adds still more layers to the conspiracies, including an expansion on the season 2 finale plot twist that introduced a parallel project, Castor, that produced a series of male clones, all played by Ari Millen. In the early going, Millen isn't asked to be a chameleon on Maslany's level, but his clones still have specific identifying marks: Mustache Clone, Scarface Clone, Soldier Clone, etc.

Earlier this week, I got on the phone with the show's co-creator, Graeme Manson, to ask him how much he thinks is too much when it comes to the conspiracy and the number of clones Maslany can play, and how the writers make sure it all makes sense both to them and to their audience.

At what point did you decide you were going to introduce boy clones? Did you know when you cast Ari that he would be playing the clones, or was there something you saw in his performance that let you know he was up for this?

Graeme Manson: We knew where we were going at the end of season 1. It had been a long-time idea, part of the weave of the mystery of introducing Castor. Going into season 2, we were keeping it in our pocket and asking, "Who's it going to be? Who's it going to be? Are we going to cast someone new?" And then Ari knocked it out of the park in the first episode in the diner scene.  By episode 4 or 5, John (Fawcett) was pretty adamant that we shouldn't kill Ari, we should keep him around and do more with the character. Then episode 8, 9 hits, and we go, "Who's the male clone going to be?" After a lot of debate, we figured that looping back, we could make it work and make it make logical sense. Ari got the tap and he was pretty excited.

In terms of looping back and making sure things made sense, did you do the same for Paul in figuring out if you could reconcile all his actions in the first two seasons as coming from a deep cover operative for Castor?

Graeme Manson: That's part of the process of a lot of the characters: Leakey, Delphine. It's part of telling the mystery: can you have revelations that lie within your cast and within your own mythology and still have them make sense? When you're mining backstory, it's one of the tricks.

When you were looking back with either of those characters, were there any moments where you had to pause and ask, "Wait a minute, does this really make sense?"

Graeme Manson: Yeah, all the time. But I think it all tracks. It doesn't get past the writers room if it doesn't track.

But you're in that writers room talking about the show at a length and depth that even your most devoted fans probably don't. How do you make sure that the mythology, especially as you add more layers to it, is something that is coherent to the audience and not just to you guys in the room?

Graeme Manson: It's a process of everyone involved in the show going, is this logical, and what can we do to reinforce it? All the way from the writers room through production and the art department and all our executives, and the net execs, too. We get read and vetted for clarity the whole way, from our crew, right up through editing. That's the trick. But if there's a certain point where you can't use all your cast at once, once you've expanded the show, so you've gotta rest people or gotta kill people or otherwise get them out of the show for a while and drop storylines. But telling a complex story is what we set out to do. We're not going to spoonfeed the audience. It's part of what our fans appreciate about the show, is it does make you think.

Do you feel like there's a point at which the mythology can expand beyond what the show is capable of supporting the weight of?

Graeme Manson: That's the point you're always trying to avoid.

But do you have a sense of what that point is? Could there be three other organizations above the current one, or are you running out of new organizations that can come in and be responsible for all of this?

Graeme Manson: No, I think that conspiracies work in layers. If you think about the shows that do it well, like "X-Files," you can keep having revelations about the broader conspiracy. The key is to keep the story centered on your characters, and keep your characters alive and making logical decisions within this framework. Let's face it: this is sci-fi. If you can keep your characters rooted and anchored in making real decisions, then that's your world. You can exist in that world that is complex and has other steps if you keep it interesting, and try as hard as you can to keep it logical.

At the end of last season, you set up Michelle Forbes as the face of the new conspiracy, but she's not in these early episodes. Was she just not available, or did you decide you'd rather use a pre-existing character like Delphine in that role?

Graeme Manson: It was a little mix of both. Michelle is a very busy actor, and with a cast our size, we can't option everyone. In a pinch, our solution was to look internally and use Evelyne Brochu. The bottom line is, that was the best to include one of the characters we really knew more to be connected to that bigger mystery. It helps us invest, to see the conspiracy through a character's eyes that we know very well, rather than someone a bit omniscient.

Alan Sepinwall has been reviewing television since the mid-'90s, first for Tony Soprano's hometown paper, The Star-Ledger, and now for HitFix. His new book, "TV (The Book)" about the 100 greatest shows of all time, is available now. He can be reached at