Jessica Chastain, Eddie Redmayne star in chilling trailer for true crime drama The Good Nurse

Jessica Chastain is ready to portray a new kind of superhero — one that actually exists in the real world.

EW has an exclusive first look at The Good Nurse, a true crime thriller based on real events starring Chastain as the nurse who went above and beyond the Hippocratic Oath to save countless lives by stopping one of America's most prolific serial killers.

Based on the book The Good Nurse: A True Story of Medicine, Madness, and Murder by Charles Graeber, the film tells the story of Amy Loughren (Chastain), a single mother working hospital night shifts as a nurse while struggling with a life-threatening heart condition. Already stretched to her physical and emotional limits by her demanding job and schedule, she soon becomes suspicious of her new coworker and friend Charlie Cullen (Eddie Redmayne) after a series of mysterious patient deaths spark an investigation, and all evidence seems to point to him as the prime suspect. Amy ultimately risks her life and the safety of her children to uncover the shocking truth about Charlie — and the chilling, unsettling reasons he was able to get away with his actions for so long.

When Chastain first read the script for The Good Nurse — written by Krysty Wilson-Cairns — she was horrified to learn that everything in the movie really happened. "I live in New York and I had no idea who Charlie Cullen or Amy Loughren were," Chastain tells EW. "Learning about this story and that it actually happened, I was very disappointed in the hospital system and for-profit medicine and the idea that this could go on for so long and be covered up. And I was incredibly impressed with Amy Loughren because without her it would've continued to go on."

Chastain felt honored to portray Loughren and bring her story to life, since "she's a real-life superhero."

"We make so many movies about superheroes," she adds. "My dad's a fireman paramedic, my brother serves in the military — so often we're surrounded by people who are doing the work to make all of our lives healthy and safe, and oftentimes they go unnoticed, so I was really excited about using this opportunity to amplify her and her story and her courage."

When Redmayne was initially sent the script for The Good Nurse, he immediately dove into Graeber's book to learn more about Loughren's story. "I couldn't believe I didn't know more about it," Redmayne tells EW. "The script itself and then Charlie Graeber's book were an astonishing revelation. What struck me was that [Cullen] did show and demonstrate great empathy, and weaponized his empathy so extraordinarily against these vulnerable people. It was really frightening to see how someone — as damaged and with his history, how he could've got into a position in which he had such power over vulnerable people. He was hiding in plain sight."

While Cullen was fascinating in a macabre way, it was Loughren's actions that ultimately inspired Redmayne. "This heroic nurse was able to do things that the police and the hospital system weren't able to accomplish," he says. "And one of the things that I think is so intriguing is that she used compassion and empathy to finally get through to this person who was doing terrifying things. We live in a world in which violence is tackled with violence and here, violence is tackled with compassion. That, I hope, is something to take away [from watching this film]."

Chastain met the real Loughren while preparing to portray her. The Oscar-winner says hearing firsthand what Loughren was able to accomplish on her own was invaluable. "It really is kind of the tale of David and Goliath," Chastain says. "Because hospitals are filled with incredible human beings, the surgeons and doctors and nurses and paramedics and technicians, everyone who works there — and here's this incredible woman who stood up against this corporation, this for-profit situation, and did the right thing."

While true crime thrillers are currently in vogue, Chastain was more attracted to this project by not only the facts behind the case but also in how director Tobias Lindholm brought the characters and story to life with a great sense of care and humanity. "Right now there's so many true crime things to watch, and you see it with cable news, this kind of desire to learn about something salacious or gossipy," she says. "I wasn't really interested in that aspect of it. I was more interested in the cost of a human life and how the system failed everyone in this story. I wasn't interested in any kind of sensationalism, and neither is Tobias — there's a great dignity to the way he works and he can tell a story that's interesting, that makes us feel connected as a society, but also he does it in a way that makes us feel whole and healthy and there's no expense. I don't feel dirty after I've watched something of his."

Watch the first trailer for The Good Nurse exclusively below:

The Good Nurse premieres in select theaters Oct. 19 and on Netflix Oct. 26.

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