There’s a chill in the air when “Gotham” returns to Fox for its midseason premiere on Feb. 29, as the Batman prequel series is set to spotlight one of the Dark Knight’s most iconic and tragic villains — Victor Fries, aka Mr. Freeze (Nathan Darrow), a scientist who turns to criminal methods to seek out a cure for his wife’s terminal illness.

He’s not the only new player in town in the back half of the season, which is ominously subtitled “Wrath of the Villains” — this week’s episode also introduces BD Wong’s Hugo Strange, the puppetmaster behind both Arkham Asylum and the secret facility of Indian Hill. In the underground lab, Strange and his cohort, Ethel Peabody, are performing twisted experiments on countless lost souls, including poor Bridgit Pike (Michelle Veintimilla), aka Firefly — who was severely burned after a run-in with the GCPD earlier in the season — and the corpse of Theo Galavan (James Frain).

At the heart of it all is Ben McKenzie’s Jim Gordon, who has increasingly blurred the lines of morality in “Gotham” Season 2, culminating in the shooting of Galavan in the winter finale. Not only will Jim have to struggle with a new strain of villain in the back half of the season, he’ll also be challenged by his own conscience.

Variety spoke to McKenzie ahead of the midseason premiere, titled “Mr. Freeze,” to discuss what awaits Jim and the rest of the city’s inhabitants in “Gotham’s” back half.

Where do we find Jim when the show returns, given that the midseason finale ended with him ignoring his better angels and shooting Theo Galavan?

He obviously did something that he never would never have done when we first met him, and we’re trying to track Gordon’s evolution into a more seasoned, and harder-edged cop dealing in a corrupt city. So his killing of Galavan — even if you could argue it was somewhat of a mercy killing; that Penguin would’ve beaten him to death if he hadn’t shot him — it was still, obviously, crossing a moral boundary of sorts. So we jump right into the repercussions of that with the investigation into Galavan’s death, and the suspicion that Jim was behind it … Suffice it to say that there will be significant repercussions, and not just on the job, but personally. He starts to fray, he starts to break down a bit, not just from the investigation, but from having to look himself in the mirror, and face the shell of the man he once was.

How much is the guilt weighing on him in the back half of the season, given that he’s also hiding what he did from Lee (Morena Baccarin) and everyone at the GCPD?

An enormous amount. I think he’s been carrying around an awful lot of guilt, and also a large burden even before this, which fits with the task he was up against: the sea of corruption and villainy that surrounds him, and trying to make good on all of these promises, whether it’s to Bruce Wayne [David Mazouz] to solve his parents’ murder, or to the police department, and in a way to his father, to uphold his father’s mantle and be the honest cop in the corrupt city. But the Galavan murder is really the tipping point that spirals us into a series of… really the whole second half of the season, Jim’s plot line, or the first half of the second half, really chronicles how he gets caught up in his web of lies that he’s created, and pays the price for it.

Captain Barnes (Michael Chiklis) saw how close to the edge Jim was in the midseason finale, in terms of taking out Galavan. Even if he didn’t see him pull the trigger, I’d imagine he’s suspicious of what went down. Does Jim feel that he has to keep up a facade at work, to try and remove suspicion?

Yeah, he does, and I think it’s one of the reasons why we cast Michael Chiklis, to give the weight of the inner turmoil inside the GCPD, from Gordon’s perspective, all the significance that it should have. And Michael obviously knows how to play those scenes so well. Whether the greater police department is aware of it or not, [Jim’s] starting to feel like a traitor, both to himself, and to the ideals that he’s held previously, and that starts to wear him down, and fray his relationship with Lee, and then ultimately, I can’t give away exactly what happens, but he gets himself in trouble, and ends up, in a way, paying the price for what he’s done, even though it’s not directly related to Galavan’s murder.

What can fans expect from the introduction of Mr. Freeze?

Like all of the villains that we’ve been portraying, we’re trying to show how they started off as real humans who are motivated by the same things that all the rest of us are; they’re just as flawed and needy as the rest of us, and Mr. Freeze is no exception … He’s motivated to freeze his wife so that he can find a cure for her disease, and save her life, so he’s motivated by the most noble of instincts, and yet he goes too far. He becomes so hell-bent on finding a solution that he’s experimenting on all kinds of people, trying to perfect his technology, and effectively killing them in the process, and so, it’s a tragic… I don’t know if the right Shakespeare reference is “Romeo and Juliet,” but it’s a tragic love story at the heart of one of the great iconic villains. So it’s an opportunity to really show something that’s not only visually distinctive, and lovely, and cool, but also emotionally affecting as well.

What kind of threat does Hugo Strange pose that differentiates him from the villains Jim’s encountered up to this point?

His villainy is in his brilliance, and his absolute, cold-blooded manipulativeness. He’s the puppet master, he’s the one who is adjusting the circuitry of people whose circuit boards are already broken, and he’s tuning them in wrong way. He’s tuning them even more to be demented, and to embrace their darker impulses, and so, that presents, in and of itself, a formidable foe for Jim. First of all, he has to understand what’s going on, which isn’t going to happen overnight, and then he would have to combat it in a way that’s different from simply getting a gun or punching somebody in the face — he’s got to figure out how to play chess with somebody. Before he was playing a bit of rough and tumble checkers, and now he’s trying to learn chess.

The show seems to have found a new confidence in its second season; how much do you talk to the writers and discuss Jim’s arc, and the story as a whole, given that you’ve now been inhabiting the character for a while?

I talk to them quite a bit. The writers’ room is in LA, and we shoot New York, obviously, so the practicality of it means that it’s much more on the phone, but they’re out a lot, and I talk to Bruno [Heller, the showrunner], and Danny Cannon, and John Stephens quite a bit. Thankfully we all have very similar taste, in terms of what we’d like to do, and what we’d like to avoid doing, and so it all works out pretty well. What we really had after the end of the first season was an exhaustive debrief of what worked in the first season and what didn’t, and quite frankly, there were a lot of things that didn’t work, and a lot of paths that we went down that we shouldn’t have, but there were many that were fantastic, and deserved further exploration. And then there were some that we hadn’t gone down, but we could see that they were available, and we needed to just open up the door a bit and plunge forward, so we did that.

I think the writers have done a phenomenal job this season of really sticking to the core … at its core, this really ought to be a serialized origin story, and not a crime-of-the-week kind of thing, and all of our villains ought to be iconic — or at least as many as we can, even if we’re, in essence, reinventing them in a sense, because no one’s seen them in their formative stage. We shouldn’t be creating these villains that people have never heard of, and they don’t really care about, and we certainly shouldn’t be introducing them and then killing immediately; no one cares, it’s not “Law & Order.” [Laughs.] So we’ve figured that part out, and then we’ve also, I think, really tapped into one of the underlying themes, the darkness that pervades Gotham, and how it seeps into every single soul within it, including our hero, and that’ll pay off here in the second half of the season. It’s made the whole thing much richer and deeper, and one of the challenges moving forward is just to figure out which stories you want to tell versus all of the thousands of stories that are out there. It’s sort of an embarrassment of riches in that way. There’s a lot of fool’s gold out there, some things that we don’t need to tell — we need to stick to our strengths and focus on them.

“Gotham” airs Mondays at 8 p.m. on Fox.