Over the course of a her 60-plus-year career, which began when she appeared as a child actor in director William Wyler's 1961 drama "The Children's Hour" alongside Shirley MacLaine and Audrey Hepburn, Veronica Cartwright has, in addition to many other roles, starred in some of the most memorable horror films ever made. She worked with Alfred Hitchcock on "The Birds," Ridley Scott on "Alien," and Philip Kaufman on his terrifying remake of "Invasion of the Body Snatchers," just to name a few.

Now, Cartwright has returned to the horror genre for writer/director Stevan Mena's "The Ruse," and in it she gives one of the best performances of her career as a dementia-afflicted musician whose home contains myriad mysteries for the young nurse (Madelyn Dundon) who has taken a job as her caregiver. As the nurse is terrorized by numerous unexplained occurrences, she tries to figure out if the house is haunted, if her patient or any of her eccentric neighbors are out to get her, or if the source of her trauma is some combination of all of the above.

Mena's twisty screenplay and elegant, restrained direction keep the audience guessing, and one of the great pleasures of "The Ruse" -- which is the kind of smart and stylish pleasant surprise one always hopes for when taking a chance on low-budget horror -- is the way that it plays fair with its characters and premise. The film has enough shocking surprises to make M. Night Shyamalan jealous, but they're all meticulously layered into the script and well earned; all of the twists grow organically out of the characters Mena has so carefully developed.

Cartwright's performance is central to the film's impact, as she creates a character who could plausibly be the film's villain, victim, or heroine, depending on one's perspective as the plot unfurls. Among other things, hers is one of the most convincing and accurate portrayals of dementia ever seen in any film, horror or otherwise; it's a performance that's heartbreaking, funny, frustrating, and terrifying in equal measures.

For Cartwright, the character's anger as someone who had devoted her entire life to a music career that was no longer available to her was key. "When she talks about music, she's very much alive because that's what her life has been, and she has just ignored everything else," Cartwright told IndieWire. "And then she's got this dementia thing which just pisses her off, but I don't think she's a mean person. My mother had dementia, so I just channeled my mom, who would get very angry if she was told she couldn't have something or do something."

Cartwright credited Mena and cinematographer Cory Geryak with transcending the limitations of their budget and schedule to create something beautiful, though she said as an actor she doesn't really see the job as being any different from when she's on a big-budget epic like "The Right Stuff." "I always write biographies for my characters and know who they are," Cartwright said. "It doesn't matter whether it's big or small, it's the same reality, and you just have to listen. Listening is the main thing, because things can happen which are unexpected, and you have to be able to go with the flow in character."

Cartwright says that her ability to "go with the flow" is probably what got her the job on "The Children's Hour," when someone off screen fired a gun during her screen test and she went with it, pretending it was wartime and bombs were dropping outside. "What made me think of bombs in London, I have no idea, but I'm convinced it's what got me the part," Cartwright said. "I just went with the moment, and apparently the other kids freaked out and looked around saying, 'What's that?'"

Cartwright's co-star Shirley MacLaine took the child actor under her wing, and Cartwright credits MacLaine with the longevity of her own career. "She was just lovely to me and is the reason I continue to do what I do," Cartwright said, noting that there was a period in between her career as a child in movies like "The Children's Hour" and "The Birds" and as an adult when it was hard for her to get work. "I was either too young or too old and I didn't fit in anywhere. I went to acting classes and studied with Jack Garfein for three-and-a-half years, and then I did improvisational theater so that I had a full repertoire."

By the time Cartwright returned to acting on screen with a part in "Inserts" opposite Richard Dreyfuss in 1975, she found that her instincts as a child and formal training as an adult had found the perfect balance. "I realized that there were a lot of things I was doing naturally as a child coming off of 'The Birds,' just knowing that if you listened and paid attention, all the emotions would be there," she said. "You don't think of your dead dog or anything like that. But it was nice to have it concrete and know what I was doing."

After "Inserts," Cartwright began working steadily again with a wide range of directors, from New Hollywood stalwarts Jack Nicholson ("Goin' South") and Bob Rafelson ("Man Trouble") to "Mad Max" maestro George Miller ("The Witches of Eastwick") and indie auteur Todd Field ("In the Bedroom"). Looking back on the many great directors she worked with, Cartwright says they're all completely different in their approach and temperament, often in unexpected ways -- the legendary Alfred Hitchcock, for example, wasn't at all imposing.

"I never felt intimated by him," Cartwright said. "It was so interesting. I got 'The Birds' because of 'The Children's Hour.' Hitchcock requested to meet me, so I met him in his bungalow and he proceeded to tell me the best wines to get, and how his favorite wine cellar was in Bristol where I was born, and how to cook a steak because some year I would get married ... all of these bizarre things, and I'm thinking 'OK, what am I supposed to do with this? I'm 12!'"

Throughout the shoot, Hitchcock taught Cartwright the secrets behind the magic of movies, explaining how he planned to get his bird effects and trick the audience's eye. "He said, 'If your eye sees movement, you assume everything is alive,' and it's true. To this day I can look at that jungle gym, think I've spotted a fake bird, and then it moves."

Even at the time, Cartwright knew how special her time with Hitchcock was. "How many times does somebody get to experience that? This man was a legend, and I would have tea with him every afternoon."

When she worked with Ridley Scott on "Alien," Cartwright quickly realized that she was working with someone who had a meticulous eye. "His whole background was as a graphic artist, so he was very interested in what everything looked like," she said, noting that his direction of actors tended to be blunt and direct. "There's a scene where I slap Sigourney [Weaver] across the face, and every time I went to do it she ducked. Ridley turns to me and goes, 'Just fucking get her this time.' So she ducked and I brought my hand back and backhanded her," she said. "She was not a happy camper, but it worked for the scene."

One of Cartwright's favorite directors is Philip Kaufman, with whom she worked not only on "Invasion of the Body Snatchers" and "The Right Stuff," but in an uncredited cameo role in "Twisted." "Phil is just adorable and he loves actors," Cartwright said. "He listens to his actors. I remember when I got 'The Right Stuff,' I had watched footage of Betty [Grissom] and when she got off a helicopter with a straw purse that had flowers on it, I thought, 'I have to have that purse.' And I always remember Phil going to wardrobe and saying, 'Listen to what she says, because her instincts are always right.'"

In this case, the freedom Kaufman gave Cartwright led to one of the film's iconic images, of Betty Grissom showing up at the White House with that straw bag. "It was so quaint and wonderful," Cartwright said, "and part of what made her character so heartbreaking."

A few years after "The Right Stuff," Cartwright got to play in an entirely different emotional register in George Miller's "The Witches of Eastwick." "George was great, and I loved that character because you got to totally go out there and nothing was too much. God, that was fun," she said. "You don't get those very often, but I've been very lucky with the people I have worked with."