Rattlesnake doesn't take long to set up its high concept. Within 10 minutes, Katrina's (Carmen Ejogo) daughter Clara has been bitten by a rattlesnake and Katrina meets a mysterious woman in a trailer who says she'll help.
The bite disappears and when Katrina takes Clara to the hospital, it seems that everything is fine. The doctor suggests it was just "exhaustion, mild dehydration", adding that Katrina might have hallucinated it all: "If a 5-year-old was bitten by a rattlesnake, you'd know it."
But she wasn't hallucinating it. And things soon get worse. A mysterious man visits Katrina at the hospital to talk about her "payment" for Clara's recovery. "Her little soul was spared. And now you owe one in return," he tells her. "The soul you take can be any one of your choosing, but it must be human, and it must be paid in full and on time."
He gives her until sunset to repay the 'debt', otherwise Clara will die from the rattlesnake bite. Katrina doesn't initially believe it, but when she goes back to the desert road, the trailer has disappeared and she sees a trucker with an eye missing warning that Clara is "gonna die".
Katrina discovers that the city of Tulia, Texas where she's ended up has been linked to a series of brutal murders and mysterious disappearances. Any time there's a photo or video of the crime scene, there's a mysterious shadowy figure in the background.
The guy who visited her at the hospital is actually a lawyer who was fatally stabbed by a school teacher (with the teacher saying "a soul for a soul" as he stabbed the lawyer), while a creepy kid who spooks Katrina actually went missing back in 2010 After an aborted attempt to kill a dying old man in the hospital, Katrina sets her sights on Billy (Luke Cage star Theo Rossi), an abusive boyfriend she sees criticising his girlfriend in a bar.
She breaks into their home and forces Billy to drive to a remote canyon in the desert. Before Katrina can kill him, though, he fights back and runs away. With time running out before sunset, Katrina prepares to kill herself, but as she films a goodbye message to Clara, Billy hits her with a rock and she blacks out.
Fortunately for her, she wakes up just in time and when Billy is bitten by a rattlesnake, Katrina takes the opportunity to kill him to save her daughter. As she's watched over by mysterious figures on top of the canyon, Katrina leaves the canyon and on the way home, the doctor calls to say Clara is fine. But is she really fine? When Katrina reunites with her, she sees that Clara has drawn a picture of the mysterious figure and the sun, seemingly aware (subconsciously) of what her mother had to do. And when the pair get back on the road in the final scene, Clara spots a hitchhiker by the road who Katrina sees is actually Billy.
It seems that anyone who is killed as part of the sinister deal is cursed to roam the city, ready to spook the next person who happens to need the mysterious woman's help to cure a rattlesnake bite.
Everyone who threatens Katrina with the death of her daughter during Rattlesnake is one of the victims of those deals – whether it's the lawyer in the hospital, the trucker in the desert or the photographer she sees in the canyon.
- Carmen Ejogo as Katrina Ridgeway
- Theo Rossi as Billy
- Emma Greenwell as Abbie
- Richard Lippert as Dying Man
- David Yow as Charlie
- Joy Jacobson as Loraine
- Arianna Ortiz as Francine
- Catherine Haun as Loraine's Sister
- Debrianna Mansini as The Woman
- Sean Dillingham as Dr. Hayes
- Stephanie Hill as Neighbor
- Jenna Doolittle as Female Nurse
- Alexandra Nell as Hiker
- Melissa Chambers as Disheveled Woman
- Tim Stafford as Male Nurse
- Apollonia Pratt as Clara
- Bruce Davis as The Suit/ Donald Covington
Rattlesnake was released on October 25, 2019 on Netflix.