The Last Time I Lied is a psychological thriller by American author Todd Ritter, written under the pen name Riley Sager. The novel, published in 2018, tells the story of three girls who mysteriously vanish from an elite summer camp. Fifteen years later, Emma Davis, who shared a cabin with the missing girls, returns to camp as a painting instructor, determined to face her childhood trauma and learn the truth behind her friends’ disappearance. However, Emma must untangle a web of lies and deceptions, including her own unreliable memories, to unravel the mystery.

This guide uses the 2018 Penguin Random House Kindle edition of the novel.

Content Warning: Both the guide and the novel contain references to drug and alcohol addiction, suicidal ideation, and outdated and stigmatizing attitudes toward people with mental health conditions.

Plot Summary

When Emma Davis is 13 years old, her parents surprise her with a summer at Camp Nightingale, an exclusive all-girl summer camp in upstate New York owned by billionaire Franny Harris-White. Emma arrives hours late and must share a cabin with three older girls: Vivian, Allison, and Natalie. Emma settles into camp life as Vivian, the girls’ ringleader, shows her the ropes and offers to be her “big sister” for the summer. Vivian’s favorite game is Two Truths and a Lie, and the girls spend their evenings whispering secrets and trying to trick one another with their answers.

When Emma sees Vivian having sex in the shower with someone she assumes is Theo, Emma’s crush, she is devastated. Later that night, Vivian, Allison, and Natalie sneak out of the cabin and vanish. As the last person to see the girls, Emma feels guilt and anxiety after the disappearance. She also keeps a terrible secret: Just before the girls left, Emma told Vivian she didn’t want to see her again. In the aftermath of the disappearance, Emma admits to the police that Vivian had a secret relationship with Theo, making him the prime suspect.

Fifteen years later, Emma is a successful painter still traumatized by the disappearance of her cabin mates. Over and over, she paints the three vanished girls on giant canvases and covers them with trees and branches until they are invisible. Franny Harris-White attends the opening night of Emma’s gallery show and invites Emma to lunch, where she makes a shocking offer. Franny plans to reopen Camp Nightingale, which closed after the girls’ disappearance, and she wants Emma to return as a painting instructor. Emma agrees, thinking she can use the opportunity to uncover what happened to her missing friends and atone for her “sins.”

Back at Camp Nightingale, Emma returns to her old cabin, where three girls named Miranda, Sasha, and Krystal are staying. Emma is on edge from the start, and strange occurrences make her feel like someone is watching her. When she discovers a surveillance camera outside her cabin, Franny and Theo (who is serving as the camp’s nurse) admit that they know about the mental health crisis Emma experienced in the aftermath of her trauma and say that they placed the camera there as a precaution. Later, Chet, Theo’s brother, visits Emma and explains that Theo was traumatized by the girls’ disappearance and Emma’s false accusation. He hopes Emma’s presence will clear Theo’s name and bring him some “closure.”

Meanwhile, Emma learns more about Camp Nightingale’s history after discovering Vivian’s diary from 15 years ago. She learns that a private psychiatric hospital called Peaceful Valley used to exist on the camp’s property. The doctor who ran it, Charles Cutler, took women from hospitals in New York City, brought them to his institute, and sold their hair to wigmakers. She thinks the Harris-White family must be hiding this secret and worries that her cabinmates vanished because they came too close to discovering it.

Things worsen when Miranda, Sasha, and Krystal go missing. As the detective questions Emma, it becomes apparent that she is the only suspect. As a teenager, Emma was hospitalized for mental illness, and now her hallucinations of Vivian are returning. Frantic, Emma confronts the Harris-Whites about Peaceful Valley Asylum. Lottie, Franny’s assistant, explains that her own great-grandfather wanted to create a place where impoverished patients with mental health conditions could receive high-quality treatment. However, the venture was too expensive; Peaceful Valley had to close, and he sold the land to Franny’s grandfather.

Embarrassed about her mistaken assumptions, Emma sets off, determined to find the girls. She canoes across the camp’s lake in the dark and follows a trail of pages from Krystal’s comic books to find the girls trapped in an old root cellar. They are frightened but unharmed, but as Emma frees them, she is surprised by Theo and assumes he is the culprit. As she and the girls run, Emma crawls into a crack in a boulder to hide. However, she accidentally slips deeper into the cave, falling into an underground cavern filled with water. Cold and injured, Emma thinks there is no way out. However, as dawn arrives, she notices the cavern filling with light and discovers an underwater tunnel that connects to the rest of the lake. She swims to freedom and finds herself in the middle of the lake.

Chet picks Emma up in a motorboat. She frantically tells him that Theo is responsible and tries to call 911, but he hits her over the head with an oar. He navigates them to a hidden cove, and Emma notices a rooster weathervane peeking out of the water; she recognizes it from pictures of Peaceful Valley Asylum. Chet tells Emma that it was his idea to invite her back to the camp. He wanted revenge for the trauma Emma caused his family when she accused Theo of hurting the girls. He intended to set Emma up but not to kill her. However, since she freed the girls, he must dispose of her for his own protection.

Chet raises his oar to strike Emma again but is surprised by a shot from an approaching boat, and Emma tumbles into the water. She falls through the roof of the old asylum building, and as she swims through the rooms, she notices a human skull amid a pile of bones. She sees the locket that belonged to Vivian and knows she has discovered the girls’ remains.

Chet is arrested. Months later, the detective calls Emma to tell her the bones belong to Allison and Natalie. However, none of the bones match Vivian, and the skeletons show signs of violence. Vivian herself appears at the opening night of Emma’s new gallery show. She tells Emma that Allison and Natalie were with her sister the night she drowned; they didn’t help when Vivian’s sister fell through the ice. Vivian befriended them as part of a scheme to exact revenge. She found the location of Peaceful Valley, led the girls to the spot, and drowned them.

Emma returns to her apartment and spends the whole night painting a portrait of Vivian. She intends to send it to the detective and tell him everything. She is done hiding.