Warning: Spoilers ahead for His & Hers

_His & Hers—_out on Netflix Jan. 8—is a classic whodunit, adapted from the Alice Feeney novel by the same name. Three women are murdered in Dahlonega, Georgia, and the six episodes are all about the search for the culprit.

Dahlonega is a very small town. Case in point, investigator Jack (Jon Bernthal), and the Atlanta reporter covering the murders, Anna (Tessa Thompson), are married but estranged. The reporter also knew the victims from her preppy high school; they were in the same friend group. Despite these close ties, the identity of the murderer catches her completely by surprise.

Here’s what to know about the show’s shocking ending.

Small town, big drama

The show starts with Anna returning to her reporting job at an Atlanta news station after a yearlong leave of absence following the death of her baby, Charlotte, who died suddenly while Anna’s mother Alice (Crystal Fox) was babysitting her. For a year, Anna has shut everyone out—fleeing from her husband and ghosting her mother. Back at work, she is furious that preppy blonde Lexi (Rebecca Rittenhouse) is at the anchor desk in her place. Her boss wants Anna to prove she’s worthy of her old job again, so she offers to cover a murder recently reported in her hometown of Dahlonega, in which a young woman was stabbed 40 times in the woods.

She arrives in town at the local hotel with a cameraman who happens to be Lexi’s husband Richard (Pablo Schreiber). Jack is surprised that Anna would come all the way from Atlanta to cover the case when he hasn’t heard from her in months. But both Jack and Anna care deeply about Anna’s mother Alice, who appears to have dementia. It’s painful for Anna to watch her mother struggle with daily tasks.

As for Jack, he lives with his sister Zoe (Marin Ireland) and her young daughter. He also has messy ties to the first murder victim, Rachel. They had been having an affair, and Jack even saw Rachel the night she was killed. When recent call logs to her cell phone turn up Jack’s number, his deputy Priya (Sunita Mani) starts to wonder if her boss is the murderer.

It’s revealed that Anna knew Rachel in high school, but hasn’t been in touch with her. During the investigation, the headmaster of Anna’s school, St. Hilary’s Academy, is found dead, as well as Jack’s sister Zoe. Like Rachel, these women had red friendship bracelets. Turns out Anna had made these friendship bracelets for all of them because they were in the same clique. A falling out is alluded to, but the reason why is kept a mystery for most of the show.

A turning point comes when Anna and Richard find out their hotel room has been mysteriously cancelled. Richard suggests they go to Lexi’s family’s lake house nearby, and Anna is shocked to learn that Lexi not only has ties to the area, but was also a member of their clique.

Mean girls

While looking at family photos on the wall of the lake house, Anna sees photos of her high school classmate Catherine Kelly juxtaposed with photos of the woman Anna knows as Lexi Jones and realizes they are the same person. Viewers see painful flashbacks throughout the show of classmates teasing Kelly about being overweight and daring her to drink urine. But after high school, Kelly had a total body makeover, and that’s why Anna never knew that her work nemesis was in her same friend group.

Rebecca Rittenhouse as Lexi in His & Hers. Netflix

All of a sudden, Anna and Catherine—now Lexi—are standing face to face in the lake house, and viewers are about to find out the big secret that drove apart Anna and the girls. Anna distanced herself from the clique after her 16th birthday, when Rachel had invited some older guys to meet them in the woods to drink and party. The men sexually assaulted Catherine and Anna. 

So while Anna has been mad at Lexi for taking her job, Lexi has been mad at Anna for taking her childhood. “You lured me into the woods 20 years ago,” Lexi seethes. She resents that Anna kept inviting her to hang out with those women because they bullied and abused her. Now, Anna is convinced that Jones killed Rachel and Helen and Zoe to get revenge.

They end up in a knock-down, drag-out fist fight that ends with them falling backwards into a glass coffee table. Lexi sees a gun laying on the floor nearby, crawls to it, and aims it at Anna, but it’s empty. In that moment, detective Priya fatally shoots Lexi, having rushed to the house after making the connection from a yearbook and the trail of friendship bracelets that Anna, Lexi, and the victims all knew each other.

When Jack gets to the scene, Anna explains that she always wanted to tell him about the assault, but didn’t know how to approach the subject because his sister Zoe was one of the bystanders. She just decided to move on and pretend it never happened. But the revelation doesn’t drive them apart. In fact, it brings them back together.

An unexpected culprit

The finale takes place a year later, when Anna is anchoring at the news station while pregnant with another child with Jack, and co-parenting Zoe’s daughter with him. They are visiting her mother’s house when Anna finds a handwritten note addressed to her.

In a huge twist, Alice reveals that she is the one who killed Rachel, Helen, and Zoe. And she’s been pretending to have dementia so that she is not suspected, but her detailed letter shows her memory is “as strong as a bear trap,” as she puts it.

After Anna disappeared when Charlotte died under her watch, her mother watched every home movie Anna recorded with her cam-corder throughout her teenage years to feel closer to her daughter. When she found a tape that showed the assault on Catherine and Anna, she decided she had to kill Rachel, Helen, and Zoe. Viewers will see her mother approaching Rachel in the forest—where she usually met men—and pushing her on top of the roof of her car, plunging the knife into her repeatedly. Then she slit Helen’s throat in her office at the school; she knew her way around because she had worked there as a janitor. And she broke into Zoe’s home and killed her while she was taking a bath.

“Killing Rachel brought you home. Killing Helen kept you here. And killing Zoe gave you the family you lost,” Alice wrote. 

She figured she could get away with these murders because, as she argues, serial killers aren’t typically women or senior citizens. While she’d planned to frame Catherine for the murders, she writes that she wasn’t too sad to see that Priya killed her. She says she hoped the killings would demonstrate the power of a mother’s love. The show ends with Anna and Alice catching each other’s eye and exchanging a smile across the house. This revelation will be their little secret.