Now available on Blu-ray is Mercy, Peter Cornwell's feature length adaptation of Stephen King's short story Gramma, which follows a single mother (Frances O'Connor) and her two young sons as they move into a remote country estate to care for her ailing mother, Mercy (Shirley Knight).  Unlike most grandmothers, Mercy isn't all candies and kisses on the cheek, and as her prognosis gradually worsens the family learns shocking truths about the source of Mercy's darkness.  Mercy also stars Chandler Riggs, Mark Duplass, Dylan McDermott, and Joel Courtney.

Early last year I joined a handful of journalists on set while they were filming in Simi Valley. While there we had an opportunity to interview McDermott, who plays family friend Jim Swann in the film. He talked about how different Mercy is to American Horror Story, why he likes working in horror, why he thinks the genre resonates with today's audience, his favorite horror film, how Cornwell's past in animation influences his directing style, and more. Check out what he had to say after the jump.

So tell us about your part. I'm curious because I remember seeing the original short movie on The Twilight Zone a long time ago, so I'm presuming they're expanding the story.

DYLAN MCDERMOTT:  Oh, really? There was an original? I don't know what that version was, I can only speak to this version, but I like this guy because he's - I've been playing a lot of characters lately that have some good and bad in them, and I've been really enjoying that. I like the complication of my character. I feel like he's a lot of different things. He appears to be one thing, but ultimately he's driven by love. In an nutshell I fee like his whole motivation in life is that he feels sort of empty. His life is not working and his relationship is not working and he loves this woman, but he's caught in a marriage and he doesn't know what to do about it. He's really driven by that more than anything else, and it's the only thing he can really think about because he's trying to find, as we all are, that sense of happiness.

How does your character factor into the story in the grand scheme?

MCDERMOTT: In the grand scheme? I really can't give away a lot because it would be giving away...

The twists and turns?

MCDERMOTT:  Yeah, so I can really only speak to the fact that there's a great love that I have for Rebecca. And I'm friends with the family. I'm almost like a brother, in a way. A father figure to the kids, so there certainly is that family aspect to my character.

Was Stephen King the lure at first to get you interested in this? Was it the director? The costars? What was it that made you connect?

MCDERMOTT:  I've known Shirley Knight for a very long time. We actually did a play. We did Glass Menagerie together many years ago. So I knew Shirley and she's a family friend, so that was definitely a lure because I love her. And Frances is just an incredible actress, just to with her. And I'm a fan of The Walking Dead. Every once and while I feel like I like to dip into the genre stuff  of horror, and I think that Blumhouse does a great job with horror and their movies are very successful. I think as an actor you have to - I, at least, try to show up in different genres. Be it a comedy in The Campaign, or be it on TV with American Horror Story, Mercy, I just finished a thriller in Canada. So I'm always trying to pop up in different genres, what interests me. Sometimes I just like to throw myself into new situations to see what it feel like?

How does it feel?

MCDERMOTT:  It feels good [laughs]. It feels very good.

How long have you been shooting?

MCDERMOTT:  Oh, not long. Just a couple days.

What about the genre is changing that's making it more appealing to you than maybe ten or twenty years ago?

MCDERMOTT:  I think everything keeps changing. There was a time when television was a bad thing for actors and it meant that you could only do television, and now we see everyone does television, right? So I think again with the horror genre for along time actors didn't do that either, they stayed away from that. And now that has changed. Everything keeps changing. People want to label things all the time and once you label it, it changes again. So I think that we just have to embrace the change of movies, of television, of genres. It's kind of like the Wild West right now. Anything is possible. I just saw House of Cards on Netflix. Who would have thought that? The idea of giving you thirteen episodes you can watch as quickly as you want.

Did you binge watch it?

MCDERMOTT:  Yeah, I watched a couple of them. I thought it was very good. Certainly the internet hasn't been figured out, and I'm sure that's next. Actors will say, "Oh my god, I'll never do a show on the internet." That will happen. You know what I mean? I'll never do a show on the iPhone, and there you are. How did I end up on the iPhone? I think you just have to be open.

Why do you think actors are more willing to step in to horror than they might have been in the past?

MCDERMOTT:  Really, to be honest with you , I think that they're successful. It's hard to find success and it's hard to find hit movies or hit TV shows and to stay relevant. I think it's a very difficult thing for actors, because a lot of us get lost, frankly. You'll see many actors who are, "Oh my god I forgot about this guy. I forgot about that woman." I think the most important thing for an actor is to stay current and stay relevant, and those are probably the hardest things to do. I'm keenly aware of that and I know what it's like. I think it's really important to keep your head above water, and certainly the horror genre is a huge market.

What separates this, and maybe in comparison to American Horror Story, what sets Mercy apart form the pact?

MCDERMOTT:  I think, again, it's the pedigree. You're not having a bunch of high school kids in this movie and it's not a slasher movie. I think it's very good actors and anytime you have good actors it raises the material and raises the bar and hopefully makes the movie better. I think that's always the attraction. You start with the script, you look at the director, you look at who's involved, and all those things seemed to add up with this project. I think it raises this movie above maybe other horror movies that are out there.

Given that the film features two kids, do you think that the stakes are raised a little bit for the audience? Kids in peril is always a touchy subject. Do you think this film pushes any boundaries?

MCDERMOTT:  I hope so. I think it's good to push boundaries, and like you said any time kids are in jeopardy it always heightens it a little bit and makes you pull on your heart strings a little bit more. So I think that's a great thing.

What do you think the draw is for audiences, and for you as an actor, to this kind of suburban horror? We've been seeing a lot of that lately.

MCDERMOTT:  I think that always works somewhere in a movie. I did a movie with Kristen Stewart a couple years ago called The Messengers and that had a similar theme with a family in jeopardy. I think that it makes you identify with it, because we all have a family somewhere and so The idea of someone breaking into the house, or some kind of peril pulls on our heartstrings and makes us afraid. The idea of a house, someone breaking into a house, all the metaphors of horror that are always present are always good things to make you scared.

What's Peter brining to the table as your director?

MCDERMOTT:  Peter comes from animation, so I think his scope is different from most directors. He looks at it probably as he would animation, which is completely - it's great. That's what I love about working with new people, because it's where you come from. Where he comes from is radically different than other directors that I've worked with. It's interesting to me to look at something the way he does. So I try to understand where he's coming from, because I don't obviously come from animation. So it just makes me laugh, because it's completely different, but I also appreciate it.

How does that manifest itself in his directing style?

MCDERMOTT:  it's just different. Every director talks to you differently and I think that he talks from a way where maybe he sees a storyboard. He already sees the movie in his head, so I kind of enjoy that when he talks to me about the movie. Because he's so enthusiastic. I can see him giggling inside when he talks about the movie, because he has a genuine love for the process and particularly making this movie.

So you feel as though this will be pretty stylistic and visual and have a lot of that nuance?

MCDERMOTT:  I hope so, yeah. I think so. I think that's what everybody's after. Because you always want to make it a little different. You never want to have a movie be derivative, because that's the worst if you ask me. I always want to be in original material, or an original idea, or an original vision, rather than a rehash of some other movie.

Did you see his film The Haunting in Connecticut?

MCDERMOTT:  Yeah, I did. It was spooky.

You said you've only been shooting for a couple days, but have you had to delve into scenes that were really emotionally or physically taxing?

MCDERMOTT:  Yeah, we did a scene the other night in the car. I can't tell you what it was, because it would kind of be giving away the movie, but it was really kind of disturbing, and it was again, going back to the thing I talked about before with this love for Rebecca, it was all part and parcel of that. It was me and George [Chandler Riggs] in the car, kind of the culmination of my character. And you could see - even when I was doing it I didn’t realize how hard it was going to hit me, but it did. And I really liked that, because I'm really exploring now about not making concrete ideas about characters, and that's really worked for me in this film. When I did that scene, I didn’t nail anything down and all this emotion started bubbling up inside of me, and I really enjoyed that because I didn’t make any decisions, so when this scene started to happen it sort of took a life of its own. I thought it was powerful and I think it's going to be a cool scene.

Would you say there's anything in this that tops whatever Ryan Murphy brings to the table with American Horror Story and the crazy shit that he does there?

MCDERMOTT:  I think that they're really different. I just think they're so different. That is so twisted and fucked up on every level, and this is really hitting the genre, but I think that goes so outside the box of anything that's ever been on television. That's why it's so controversial and so great.

If American Horror Story is a very twisted, fucked up kind of horror, how would you classify what you guys are going for on this film?

MCDERMOTT:  I would say this is classic horror in the best sense of the word. I think that it's everything that you would want in a horror movie, all the pieces are there, all the archetypes are there. So I think that I like that because I think you need that in horror. You have to have a chessboard. You can't play chess without the bishop or the knight, and I think that everyone who's in this movie is fulfilling their role in terms of what it should be to scare the hell out of you.

Beyond what you obviously do, is there a particular horror performance, maybe from the 60s or 70s that you really admired?

MCDERMOTT:  My favorite horror movie of all time, and will continue to be, I don’t thin anything will top it, is Rosemary's Baby. To me Polanski is one of the greats in terms of psychological horror. It's just hard to top him because he's so damn good at it. When you look at The Tenant, which is one of my favorite movies, it's just so brutal and so sick and twisted. When he dresses up as that woman and he's up there talking to himself, got the heels on. It's fucking great. And then Rosemary's Baby, of course, is just the best. Really, that's just the best there is.

Mercy is available now on Blu-ray and VOD.