Chastain is an everyday superhero in ‘Good Nurse'

“The Good Nurse”

Rated: R “for language.” Running time: 121 minutes. 666 (out of four)

Movie titles are always important, but there's special significance to the title of “The Good Nurse,” based on the horrific serial killings of dozens and possibly hundreds of patients by a night nurse who injected fatal drugs into IV bags.

Of course, real-life convicted killer Charles Cullen, potentially one of the most prolific serial killers of all time, is not the “good nurse” in the title, even in an ironic sense. It is, rather, fellow nurse Amy Loughren — played by a luminous, effortlessly empathetic Jessica Chastain — who first befriended Cullen, then suspected him, then helped bring him down.

In bravely securing the evidence police needed, Loughren surely saved countless lives, because the hospitals where Cullen worked, the film argues, lacked the moral courage to act on their suspicions — firing Cullen for minor offenses and essentially leaving him to keep killing (he worked at nine hospitals.) In focusing the story on this “good nurse,” director Tobias Lindholm and screenwriter Krysty Wilson-Cairns, working from Charles Graeber's book, make a powerful argument for telling such stories not via the killers themselves — psychoanalyzing and perhaps aggrandizing them — but via those who bravely confronted them. And so Loughren, a single working mom with heart trouble, becomes an everyday superhero.

There's a simple moviemaking lesson here, too, which is that when you have a cast as talented as this, led by Chastain and Eddie Redmayne (going way darker than usual), it becomes less important if the structure seems to veer formulaic. There are, alas, moments where “The Good Nurse” has a toofamiliar TV police procedural feel, when you know just what's going to happen next and see the plot machinery moving. But the acting, especially Chastain's never-a-false-moment portrayal, triumphs over all that.

We begin with a brief prologue in 1999, at a Pennsylvania hospital. Suddenly a patient “codes,” and staff rush — unsuccessfully — to save him. Quietly watching is Cullen, standing against a wall.

Redmayne plays Cullen as someone so unremarkable, he can melt into that wall. Seemingly taking to heart a description in Graeber's book of “a sad Mr. Rogers type," he even wears a gray cardigan. Lacking definable personality, he is a true cipher.

(Redmayne also becomes yet another top British actor to display an uncanny facility with American accents.)

Now we jump to 2003, and a New Jersey hospital. Amy, the night nurse, is exhausted and overworked, but obviously devoted to patients. When an elderly patient's husband balks at leaving his wife alone overnight, Amy breaks the rules on no guests and brings him a pillow and blanket.

A single mom, Amy works nights so she can be with her kids in the daytime. She can barely pay the babysitter, let alone the private doctor treating her

heart condition, which will require surgery. She can't get care in the hospital because they'd fire her if they knew. And she still needs several more months to qualify for health insurance.. (The movie makes a good argument for how undervalued nurses are in this country, not to mention the absurd notion that this nurse who saves lives lacks her own health insurance.)

Enter Cullen, who arrives on the night shift with “great recommendations,” according to Amy's supervisor. Seemingly generous and hard-working, he immediately becomes friends with Amy,

meeting and playing with her kids, and vowing to help conceal her condition — even sneaking meds from the hospital's automatic dispensing system (he's identified a way to cancel an order but still get the drugs). Meanwhile, Amy's elderly patient dies, inexplicably. Her husband is gutted. And now, police start asking questions.

Two detectives have suspicions right away. These dogged investigators, played by Nnamdi Asomugha and Noah Emmerich (the latter latching onto the culprit far earlier than did his hapless FBI agent in “The Americans”) are stonewalled by the hospital, which is run by sleazy corporate types out to save their for-profit institution over protecting lives. Kim Dickens is chilling as a former nurse turned administrator who shills for her hospital.

As for Amy, she initially defends Charlie, but understands better than anyone how he could have gamed the system. As more people die, she discovers his tampering. But the police need more proof.

Chastain's best scenes come toward the end when she is seized with fear, yet determined to stop her friend even when it means confronting him boldly at close range as he begins to unravel. Redmayne has the task of showing us what truly mundane evil looks like. Except for one moment that feels jarring for its suddenness, he craftily displays a veneer starting to crack.

So we know whodunit, and we know how. But anyone looking for an answer as to WHY Cullen did the unthinkable won't get it here (when the real man appeared on “60 Minutes,” he basically had no answer, pulling back on an unconvincing mercy-killing claim.)

And to the filmmakers' credit, they don't manufacture a motivation where there wasn't one. There's no need. The unembellished horror of this real-life tale is way more than enough.

JoJo Whilden / Associated Press This image released by Netflix shows Eddie Redmayne and Jessica Chastain in a scene from “The Good Nurse.”