A corner deluxe room has suddenly opened up at Berkshire Oaks Senior Living at the start of “I Care a Lot,” the result of a quiet passing that leads everyone else to believe they’re about to make a killing – none more so than Marla Grayson (Rosamund Pike), a savvy entrepreneur who has found a healthy business preying upon the infirm, taking legal guardianship of the elderly away from relatives that aren’t around to provide the local care that she can and auctioning off their assets for her troubles. With her partner Fran (Eiza Gonzalez), she needs to find a mark as special as the the offer she can make to the court to avoid any suspicion about her intentions, coming to locate Jennifer Peterson (Dianne Wiest), a retiree with seemingly no family to speak of, a house she’s paid down in full and a slight amount of memory loss. Still, when Fran can be heard assuring Marla, “Just your regular old lady,” you suspect that’s anything but the case.

And while you might be right, it’s never in the way you might think in this devious delight served up with relish by writer/director J Blakeson, who returns to the same wonderfully nasty comic thriller territory of his breakthrough “The Disappearance of Alice Creed” with “I Care a Lot.” Armed with a dazzling performance from Pike, whose finely trimmed bob is only the start of how Marla gets the edge on others, the film considers a culture that has given rise to how the service industry has been infiltrated by those who serve only themselves as the legal guardian pays off Peterson’s physician (Alicia Witt) and her nursing home provider (Damian Young), leaving you to wonder if she’ll ever have to pay the piper, which appears to come in the form of a gangster (Peter Dinklage) interested in Peterson’s welfare for reasons of his own.

As gifted at using an audience’s mind against them as his central character, Blakeson brings such a sense of style to “I Care a Lot” that all of the film’s many surprises come with the satisfying angst of thinking you should’ve known better, ideal for an entertainingly twisted tale that ultimately asks one to look inward at how there became greater incentive in looking out for ourselves than one another. The writer/director has found at least one clever way to bring people together with such a crafty satire, and on the eve of the film’s premiere at the Toronto Film Festival, he spoke about how he was inspired to delve into the underworld of ill-intentioned guardians, finding opportunities to upend expectations through the movie business’ own failings when it comes to representation and the attention to detail that make his films feel so completely pleasurable.

How did this come about?

The idea first came when I heard news stories about these predatory legal guardians who were exploiting this legal loophole and exploiting the vulnerability in the system to take advantage of older people, basically stripping them of their life and assets to fill their own pockets. These stories were horrifying and not uncommon. So I fell down a bit of a rabbit hole in reading about these various stories happening in various places and thought there was something almost Kafkaesque about somebody knocking on your door and just taking you away for a reason you didn’t think was valid. They had the law on their side and there was nothing you could do, so that terrified me and I thought it was a good jumping off point for a story [about] a central character who is ruthless and machiavellian, and hopefully an iconic centerpiece for this…you know, it’s not dark, but it is kind of dark ride of a movie.

Like “Alice Creed,” there were so many times when my assumptions worked against me. Is that something you actively think about when writing this?

I guess I am unconsciously. I’m a big cinephile and I watch hundreds of films and I read a lot of scripts that get sent to me, and when you can guess what’s going to happen and then it does happen, you’re always disappointed. Whereas I like the ones where you guess what’s going to happen and then something else entirely happens, but it still makes you believe the thing you thought might happen is still going to happen — it still plays with your expectations. People are so cineliterate that you really understand what the little codes and the little gestures mean in films from the music to the cutting to little bits of performance. They know that two plus two is going to equal four, but I like films that lead you down towards four and it suddenly becomes 13. And the 13 makes more sense than the four. “Alice Creed” was like that and this one’s like that., so I guess that’s the world I like to play in.

I feel like you’ve taken so much advantage of the assumptions made about female characters as well, when they’re usually not portrayed so dynamically. Is that part of the attraction to making them your leads?

I think so. A lot of the people in my life are women, and a lot of the people you see on screen aren’t, and you look in this movie and we’ve got so many great actresses – Rosamund Pike, Dianne Wiest, Eiza Gonzalez – and again, I read a lot of scripts I get sent and [they] don’t have a lot of good parts for women in them. I was trying to think of a film that has a ruthlessly ambitious female protagonist who wasn’t a femme fatale, because [Marla’s] definitely not a femme fatale. She’s not using her sexuality at all. She’s just using her tenacity, her brain, her calculating nature and her fearlessness to achieve what she wants, which is much more like someone in “Goodfellas” or “Wolf of Wall Street” than you would normally see for an actress.

I try to make the movies I’d want to see and especially in the industry I work in, [where] half the people I know are women and they’re all very ambitious and they’re all good at their jobs, I wanted to see that and I wanted to see more of it. And I really want to work with the best actors and if you see actors who don’t really get enough to play with or are thought of a certain way, it’s great if you can see more potential in there to do something slightly different and cast them in a role they may not automatically be thought of for. For Eiza, for example, I don’t think I’ve seen her do anything quite like this before and she was fantastic, and Peter Dinklage as well, so it was a joy to be able to do that.

What sold you on Rosamund Pike to play Marla?

We met a few times and she instantly got what I was trying to do and instantly got the character and had a passion to play her, so it was very apparent she was going to be great in the role. I’d always loved her. The first time I really noticed her was in “Pride and Prejudice” some years ago, and she’d always pop up totally different in [films] like “An Education,” and “Gone Girl.” She always disappears in these roles — in “Barney’s Version,” when I was watching that, it took me 20 minutes to realize I was even watching her — and I love actors who can do that, so it’s like someone you recognize from every day life and then they’re in a movie. As much as I love watching movie stars as well, there’s something really special about an actor who can really just disappear into the role and because there’s a lot that she has to do in this movie that takes a lot of guts to do just physically as well as emotionally, she was fearless in her commitment to the character. It was so nice to see her having fun doing it and I think a lot of the actors, you can see them having fun in the scenes where they’re going head to head with each other.

You’re obviously thinking about tone when casting, but once you lock actors in, is there something about their energy that may change your ideas about this?

A little bit. These days, it’s very hard to get a lot of rehearsal time, but we got some time to play out the longer scenes and just have the actors sit in a room, talk over the script and get to meet each other first and figure out, along with myself, what we wanted the scene to be and where we wanted to go. A lot of this film is about power, so we’d figure out what that power dynamic is, but also not doing it so much that they’re not surprising each other on the day or not surprising me because you don’t want it to feel like they’re just going through the motions. With certain scenes — the scenes where Rosamund and Peter have some head-to-heads or when Dianne and Rosamund go toe-to-toe as well, there was just sort of magic happening in the moment and you try and ride that on instinct. You say, “Well, that was good, let’s do it a little bit more like that” and the actors get excited in the moment and you have the adrenaline going and it feels like it’s happening right there and then. I always had a handle on what I wanted the tone to be and I had a visual look and music, which is quite specific, in my mind and obviously they didn’t have that, so they were often relying on me to make sure that tonally we were in the right place. But luckily, they were all so collaborative and they put a lot of trust in me, which I really appreciated. They really nailed it.

I was surprised to read was that you shot in all practical locations, which is not because they looked like sets, but with the angles you shoot with and the way you furnish them, it looked like you had so much control over them. Was that a challenge to work with?

It’s always a challenge. [laughs] Even if you build sets, they’re always expensive and they’re never as big as you want them or [have] the walls to fly away. But if you know you’re going to have to shoot on location, you’ve got to let go of the pictures you have in your head and you’ve got to find new, exciting pictures on the ground. It’s like with casting. Sometimes a character’s written a certain way and then an amazing actor wants to play that role and it’s not quite as written, but it makes it more exciting because it’s not what you were originally thinking of.

We had lots and lots of locations because you had a lot of movies in this movie. [laughs] I had a really, really good production designer [Michael Grasley] and the real challenge was trying to make all these locations fit with the look of the movie. I had a very distinct, colorful look I wanted to go for that was hard to do moving fast. We spent a long time going around local neighborhoods, looking for the right house and the right office and then it was up to Michael and his team to really turn it into Marla’s office, put her character into it. We were looking for places that had good light or good space — we knew we were going to shoot in 2.35 widescreen, so [we knew] to have a low ceiling, but wide walls. It was a really collaborative process between Michael the production designer and Doug [Emmett] the cinematographer and myself to really make these locations work physically, but we all got on really well, so we just had really good fun making it work.

This may be silly to ask, but Marla’s hair becomes a real extension of who she needs to be at any given moment. Was that all mapped out for the character?

We had lots of conversations about hair – her hair and Peter’s hair. [laughs] Lori [Guidroz], who did our hair and worked with Rosamund before on “Hostiles,” and I had lots of conversations about that cut and that color. [Marla’s] introduced by her hair — the first shot we see is of her hair and it’s precise and razor sharp. When she is at her most vulnerable, her hair is not precise — she goes through the wringer, but then when and if she comes out the other side of it, her hair gives you a good indication of who has the power in the movie. It’s like Samson, it’s reflected in the hair. [laughs] I liked shooting close-ups where you get a lot of her hair because you see the hair framing her face and it was important to me for those little details to be right.

Also as we did the costumes, we had long conversations about the color of costumes and the fit of her first suits. Marla is a very precise character. Her office is very clean and symmetrical and when we first meet her, she’s organizing her things so they’re all lined up in parallel. She likes to be in control and every little thing on screen has to inform the character. It’s not just the performance. It’s everybody working around the actor to help support their performance and make it feel like it’s a real person.

There couldn’t seem to be a better time for this film to be coming out when greed seems to be so prevalent. What’s it like starting to get it out there?

It seems to only have gotten worse, but it was written in the moment as well and it feels like this thing has always been there, but the volume’s just been turned up a bit louder now. The idea of a flawed system that can be manipulated for profit and power is extremely relevant right now and that’s not just on a big worldwise stage, but on a small [personal] stage like the attitudes that you can see all around us in the culture, like the worship of wealth and success and entrepreneurialism and all that. That slightly disturbs me, so I wanted to explore it a little in this movie and hopefully even though it’s a fun ride, there will be something lingering in people’s mind afterwards that keeps them thinking about it and keeps them talking about it. I’d love this to start conversations and have people afterwards say, “Well, I really enjoyed that, but was it right to enjoy that?”

“I Care A Lot” will screen virtually at the Toronto Film Festival on September 13th at 6 pm.