Jim Holden isn’t fueled by politics or professional curiosity to untangle the elaborate mystery of Syfy’s “The Expanse.” He’s driven by guilt, says actor Steven Strait, and a desire for justice.

After all, it was Holden, the second officer of the ice hauler Canterbury, who decided to acknowledge a distress call in space, which led to the destruction of his own ship, and drew him and a handful of surviving crewmates into a far-reaching conspiracy that pushes Earth and Mars toward war.

Now Holden, who's spent much of his adult life avoiding responsibility, is forced into a leadership role to uncover who's behind this growing mystery, and potentially save millions of lives.

Strait (“Magic City,” “Sky High”) recently spoke with SPINOFF about his love of science fiction, “The Expanse’s” epic sets, and Holden’s next move.

Spinoff: You’re a fan of science fiction. What excites you about the genre?

Steven Strait: What I like about science fiction is really the flexibility that you have in telling a narrative that can be present and political and personal, but it's framed in a way within this genre that is more digestible in some ways to a larger audience. If you are talking about present politics or hot-button issues, the audience is able to objectively look at what's going on and not personalize it too much, but still relate. Science fiction is unique in that way. It has the metaphorical power, and the framing power, to talk about a lot of issues all at once.

After it all hits the fan and Holden's ship is blown up, how motivated is he by guilt as opposed to seeking justice?

It's both. I think the major driving factor behind Holden's transformation from being this cynical slacker of a guy to this inadvertent revolutionary is guilt over the outcome of his loved ones and friends, as well as the justice he wants for them. He doesn't want to be just left alone; he's now a man with a purpose. He didn't really have that before. He did want that anonymous existence, but what happened with the Canterbury changes his whole frame of reference for what his life is supposed to be about. He goes from being a guy without a cause to a guy whose cause is almost more important than the well-being of himself or the people around him. It's a pretty dramatic change. It's both guilt and the desire for justice that drives him.

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What have you enjoyed about the group dynamic between Holden and the other survivors – Naomi, Amos and Alex - because they didn't start off as friends?

No, no they didn't. That's actually what I have really loved so much about exploring these relationships, is that when you meet this group of people, they are essentially thrown together to do this search and rescue or investigate this distress call. It wasn't supposed to last more than a couple of hours. All this stuff happens and they don't know each other very well. They do on the periphery. They aren't friends really. The guy Holden knows the best is Alex, because he's on the bridge all the time. But Amos and Naomi are engineers working on the ship in various parts of what needs to be done. What I've loved about portraying it, especially with these amazing actors that I get to work with, is taking this fractious group, that doesn't particularly get along with each other, and have it grow into this tight crew that have this one experience in common. They are the only people who have this knowledge of what happened and can really truly understand what's going on. As the story starts to unfold for all the people left alive, the burden of holding on to that truth, and how alone they are, pushes them together. That whole trajectory and arc has been really fun to play.

The Canterbury and Martian vessels were destroyed. Holden and company are piecing together this cover-up/conspiracy. Recently, Fred Johnson (the de facto leader of the Outer Planets Alliance) joined the mix. How much is Holden in over his head?

Holden is completely in over his head. I think he feels he's been in over his head since he started investigating the Scopuli. It doesn't even matter to him at this point. So much has happened to them and this group of people. At this point, the unexpected is almost expected to them. I don't think he particularly trusts Fred Johnson [played by “The Walking Dead’s” Chad Coleman]. Holden just has no other option. In that way, the decision to bring him into the fold is more of a pragmatic one. They just have nowhere else to go. There is still a bit of arrogance to Holden, but, honestly at this point in the story, he's driven so much by cause that it doesn't even matter that he's in over his head. It concerns him that he's dragging other people into it, but he will do anything he needs to get justice for his friends.

Holden turned down Johnson's request to testify in front of the OPA. What's his next move, then?

I don't want to give too much away, but Holden does know he has a card to play. These survivors of the Canterbury are uniquely important to stopping whatever conflict is brewing, and in stopping whoever wants to start it. Right now, everyone is pointing a finger at each other. These survivors are the only ones who know at least who didn't do it. The truth is the only leverage he has. He uses that leverage for all it's worth because that's all he's got.

Holden and Detective Joe Miller (played by Thomas Jane) have unknowingly been working the same case. How do they approach things differently?

Miller's trajectory from the beginning is a guy who probably started with the best of intentions when he became a cop and then was ground down over the years. For him, he has an obsession with Julie Mao's case that goes far beyond solving a mystery. He feels something deeply for her. He's a very isolated character and whether or not it's actually her, or a construct of his mind, he has a passion for finding what this case is about for a personal reason. He wants to find this girl who has come to metaphorically symbolize the things that he wants for himself.

For Holden, it's a broad reason. It's still personal, but he's driven less by awe and more by anger. He simply wants to know why his friends died, who did it and to hold them accountable. They both come at the Julie Mao case with personal intentions on both sides, but they both quickly discover they are wrapped up in something greater.

The production value gives "The Expanse" this epic scope. In what ways did it help filming on these practical sets instead of a CG environment?

Watching these episodes, especially with the CG stuff, you really have no concept of how it's going to end up when you're finished. You can just hope and trust the people you are working with. We were so blessed with our visual effects team.

In terms of the practical sets, we have this incredible crew building these gorgeous sets that we horrifyingly tear down every couple of weeks or they get blown up all the time. But it makes all the difference, particularly for the folks out in space. The sets for Ceres and the sets for all the ships are so realistic. For me, and the other actors, you have to put yourself in this otherworldly circumstance. You are on this enormous Martian battleship and all this stuff is happening. To be able to actually touch the walls and make it feel like you are there, makes that whole process so much easier. You can really just focus on doing the scenes and the work, as opposed to imagining the whole environment and how you are interacting with it. It's an incredible luxury to have what we have. We have three of the largest soundstages in North America full of these sets at all times.

Lastly, Holden experienced zero-gravity sex. What other activities would be fun to try out weightless in space?

I'm waiting for the moment Holden drinks coffee in zero gravity. I'm waiting for that. Or, we can have the two things that he holds dearest and converge them into one thing. I have my fingers crossed for next season.

“The Expanse” airs Tuesdays at 10 p.m. ET/PT on Syfy.