You only need glance at the trailer or images from Ratched, Ryan Murphy's One Flew Over the Cuckoo's Nest prequel series, to know that the series is a pretty significant detour from the 1975 film, with the (extremely fabulous) 1940s costumes dominating the mood. 

While Ratched delves into how Nurse Ratched — Mildred, as we learn at the outset of these eight episodes — becomes the villain that she is, the bulk of Season 1 plops us right into the action as she begins a campaign of torment and terror for reasons that soon become clear. With strong performances from Sarah Paulson as Nurse Ratched, and a stellar ensemble cast that includes Jon Jon Briones as psychiatric hospital head Dr. Richard Hanover, Judy Davis as the put-upon Nurse Bucket, and Sharon Stone as the devious heiress Lenore Osgood, Ratched stands on its own as a work with roots in a familiar piece of pop culture. So how is the series like and not like the film? Here are some (mildly spoilery) ways. 

(*Note: these observations are based on the Jack Nicholson film, not the novel of the same film.)

1. Mildred starts her journey in different time and place 
Set in Northern California, Ratched starts in 1947, as opposed to 1970s Oregon, as in the film.

2. She doesn't have one sole troublemaker driving her mad
In the filmJack Nicholson's character Randle Patrick McMurphy comes to the Salem State hospital where Nurse Ratched works and upsets the natural order. In the series, the opposite is true: Nurse Ratched lands at a psych hospital with a very clear objective she knows will upend the order there. 

Ratched Review: Lean on Its Cuckoo's Nest Roots but Heavy on Ryan Murphy's Signature Style

3. Nurse Ratched does some pretty terrible things in the series 
In the movie, Nurse Ratched is more of an authoritative threat — a stern and uncompromising figure who rules the Salem State hospital where she works with an iron fist and cold demeanor. In all fairness, she's just trying to do her (unenviable job) when we meet her: dispense medicine, keep order, and prevent the band of patients she oversees from harming themselves or each other. It's really the introduction of Jack Nicholson's character Randle Patrick McMurphy that pushes Nurse Ratched over the edge, since he's an avowed troublemaker who makes it his mission to defy her and turn the ward's patients against her. The most awful thing she does, after revoking privileges and issuing threats, is have Randle lobotomized. In Ratched, she's capable of much worse. 

4. This Nurse Ratched has sexual desire, and a kinky side
Very little is known about Nurse Ratched in the movie, which is obviously the point of this series. But in telling her story, Ratched producers and writers dive deep into an important, unexplored part of her psyche: her sexuality. We learn pretty quickly that Mildred is sexually attracted to women but is conflicted by it, and, in keeping with the thinking of the time, deems homosexuality both a sin and mental illness. That suppression of her normal sexuality — officially deemed not a mental illness in 1973 by the American Psychiatric Association — only makes her even more prickly.  But while she denies her attraction to women in the bulk of the first half of the season, she also engages in some kinky role play sex with at least one man in the story, and their sex illustrates how disconnected she is from reality and emotion.  

5. She's got a vulnerable side
In the film, pretty much the only time we see Nurse Ratched show any softness whatsoever is after a character commits suicide, and then after Randle chokes her in anger after that event. Even then though, Nurse Ratched remains steely and cold; she's not exactly the crying or apologizing type. In the series however, we see Nurse Ratched show empathy, care, and concern — sometimes in surprising ways. She's about as manipulative and deceitful as anyone can be, but the series shows the core wound that caused her to be that way, and illuminates the triggers that make her feel compassion for others. You don't exactly come away loving her, but at least empathizing with her pain. 

Ratched premieres Friday, Sept. 18 on Netflix. 

PHOTOSFirst Look at Ratched on Netflix

  Sarah Paulson, <em>Ratched</em>  Sarah Paulson, Ratched