Bad Blood

Published in 2016, Bad Blood is the fourth and final novel in the Young Adult (YA) thriller series The Naturals by Jennifer Lynn Barnes. The series follows a group of gifted teens whom the FBI recruits for their innate talents in criminal profiling and behavioral analysis. In Bad Blood, 17-year-old profiler Cassie Hobbes and her team hunt a secret society of ritualistic serial killers known as the Masters, a case that is deeply personal because Cassie believes that they’re holding her long-missing mother captive. As the hunters become the hunted, the killers target the Naturals, raising the stakes of the investigation. Barnes, who holds a PhD in psychology and cognitive science from Yale University, draws on her academic background to explore the intricacies of criminal behavior and psychological trauma. She’s also the author of the New York Times best-selling series The Inheritance Games.

Bad Blood blends the conventions of a criminal procedural and a Young Adult (YA) thriller, using the framework of crime-solving to explore its central themes. The novel examines The Duality of Power and Control, as both the killers and the Naturals use psychological manipulation; The Moral Compromises Necessary for Survival, as the characters confront their dark pasts and make morally ambiguous choices; and The Loyalty and Support of Found Family Versus Blood Ties, as the damaging legacies of biological families contrast with the supportive bonds of the team. By fictionalizing criminal profiling as an inherited talent, Barnes uses the concept of “bad blood” to question the extent to which genetics versus choice determines one’s nature.

This guide is based on the 2023 Little, Brown and Company Revised Trade Paperback Edition.

Content Warning: The source text and this guide feature depictions of graphic violence, child abuse, physical abuse, emotional abuse, substance use, cursing, and death.

Plot Summary

Cassie Hobbes, a teenage profiler for the FBI’s Naturals program, visits incarcerated serial killer Daniel Redding. She reveals her belief that her mother, Lorelai, wasn’t murdered years ago but is alive and being held captive by the Masters, a secret society of serial killers. Redding confirms that he has heard rumors about this group. Shortly after, the team is assigned a new case: Celine Delacroix, a childhood friend of fellow Natural Michael Townsend, has disappeared. This case likewise appears linked to the Masters, as Celine vanished from a kerosene-soaked crime scene on a date aligning with the killers’ ritualistic, number-based pattern.

The team travels to upstate New York to investigate. From a safe house, Michael profiles his abusive father, Thatcher Townsend, and senses a disturbing possessiveness toward Celine. While searching Celine’s room, Cassie, Michael, and human lie detector Lia Zhang discover a hidden laptop and learn that Celine uses kerosene as a paint thinner. The investigation soon reveals that Celine faked her own kidnapping after a confrontation with Thatcher. When the team confronts Thatcher, he denies having an affair with Celine but physically assaults Michael. The emotional fallout causes Michael to cruelly tell Lia that he has loved Celine longer and better than he has loved her.

After finding Celine and closing the case, the team’s guardian, Judd, gives Cassie a file on an inmate whose wife, Mallory Mills, disappeared under circumstances identical to Lorelai’s. Seeking more information, Cassie visits her four-year-old half-sister, Laurel, who was recently rescued from the Masters. Laurel provides cryptic clues, including a seven-note tune, and alternates between her child persona and a cold identity named “Nine.” Later, Celine reveals that she’s Thatcher’s illegitimate daughter. Meanwhile, statistics expert Sloane deciphers Laurel’s tune, uncovering a defunct Social Security number for a man named Mason Kyle from Gaither, Oklahoma.

The Masters recapture Laurel, and Cassie realizes that her visit led them to her sister. Before the team leaves to investigate the new lead, Celine, who has a Natural-like talent for facial recognition, creates an age-progressed drawing of Mason Kyle from a childhood photo. The image is a perfect match for Nightshade, a Master the team previously captured. Now knowing his real name, the team travels to Gaither. Upon arriving, Cassie is struck by a sense of déjà vu and realizes that she and her mother lived there for a year, a period she had completely forgotten. At a local diner, the owner, Ree, confirms this. The team learns of a local cult, Serenity Ranch, and the unsolved murder of Nightshade’s parents. Cassie then recovers a memory of her mother’s romantic involvement with Kane Darby, the cult leader’s son. Disturbed by the case’s parallels to her own past, Lia infiltrates Serenity Ranch alone.

While Lia is undercover, the Masters’ new apprentice murders two people connected to the Naturals’ past cases. The team fears that Celine will be the next target, but she arrives in Gaither to help. The FBI raids Serenity Ranch and discovers two bodies, dead for approximately a decade, in a hidden cell. Celine reconstructs their faces from the skulls, identifying them as Ree’s missing daughter, Sarah Simon, and Kane Darby’s identical twin, Darren. Under interrogation, Kane confesses that his family imprisoned his sociopathic twin after Darren murdered Nightshade’s parents. Years later, Darren killed Sarah, escaped, and attacked Lorelai, who killed him in self-defense. Kane helped Lorelai flee and covered up the murder. However, Sloane reexamines the evidence and concludes that Nightshade’s grandfather, Malcolm Lowell, murdered his own family to groom Nightshade for the Masters. In Lowell’s basement, Cassie finds the Masters’ symbol and realizes that Lowell is “Nine,” the title for the cult’s original child leader.

The investigation reveals that the apprentice’s third target is Cassie’s cousin, Kate. Cassie understands that this is a message from her mother to drive her away from Gaither. Before she can leave, Ree poisons the entire team at the diner, revealing that she’s the poison Master who trained Nightshade. Cassie is taken to a secret location where the apprentice, a teaching assistant from a previous case, named Geoff, taunts her. Ree applies a deadly contact poison to Cassie’s neck. Cassie awakens in a hospital room with FBI Director Sterling, who reveals that he’s also a Master. He admits to killing Nightshade, orchestrating Laurel’s recapture, and tampering with Cassie’s tracker to mislead her team, all as revenge against Dean for his relationship with Director Sterling’s daughter, Agent Veronica Sterling.

Cassie is taken to a sand-filled arena and forced to face her mother in a ritualistic fight to the death. She realizes that she’s facing “Cassandra,” a dissociative identity that her mother created to endure childhood abuse. Cassie refuses to fight, appealing to her mother’s true self. Lorelai’s persona emerges, but Director Sterling holds Laurel at knifepoint, forcing the fight to resume. To save Laurel and end her own suffering, Lorelai forces Cassie to fatally stab her. Just then, the FBI, led by Agent Briggs, storms the arena. To save Laurel, Agent Sterling shoots and kills her father (Director Sterling). In the aftermath, Agent Sterling reveals that Celine helped locate them because she noticed a facial resemblance between Laurel and Sterling, exposing the Director as Laurel’s biological father. Three weeks later, Briggs is the new FBI Director. The Naturals program relocates to Denver, where Cassie’s paternal grandmother helps raise Laurel. The team, now including Celine, plans to recruit a new generation of Naturals.