56 pages 1-hour read

All In

Fiction | Novel | YA | Published in 2015

A modern alternative to SparkNotes and CliffsNotes, SuperSummary offers high-quality Study Guides with detailed chapter summaries and analysis of major themes, characters, and more.

Prologue and Chapters 1-11Chapter Summaries & Analyses

Content Warning: This section of the guide contains depictions of graphic violence and death.

Prologue Summary: “You”

An unidentified killer, described as “you,” contemplates their obsession with counting, order, and meticulous planning. They believe that anything can be quantified, from the strands of a girl’s hair to the number of breaths she has left. They reflect on their intricate plans for the girl and the person they are destined to become, viewing numbers as a principle for organizing their actions.

Chapter 1 Summary

The story begins on New Year’s Eve, with Cassie at family dinner. She has been away from her grandmother’s warm and loving house, which she now calls home, for six months with the Naturals, a fact she hides from her family. The dinner is interrupted by her estranged father, Vincent Battaglia, who tells her there is news about her mother.

Chapter 2 Summary

On the porch, Cassie’s father confirms that a body, presumed to be her mother’s, has been found. He offers Cassie a silver necklace with a red stone discovered with the body, which she recognizes. Citing evidence protocol, Cassie refuses to take it. She remembers her mother’s recurring phrase, “no matter what” (14), which was their secret code for “I love you.” Determined to solve the case, Cassie resolves to ask Agent Briggs for full access. Four days later, Judd arrives to take her back to the program, and Cassie says an emotional goodbye to her grandmother.

Chapter 3 Summary

During the drive to an airstrip, Cassie tells Judd her mother’s body has been found. Judd, whose daughter Scarlett was also murdered, already knows. Cassie requests the case files, vowing to find the killer. Judd warns her that obsession will not lessen her pain. Cassie brings up his loss to make him understand. Recognizing the parallel, Judd agrees to give her the files but forbids her from working the case alone.

Chapter 4 Summary

Cassie boards a private jet and rejoins fellow Naturals Dean, Lia, and Sloane, along with FBI handlers Briggs and Sterling. Michael is absent, and Cassie decides to keep the news about her mother private. Sterling notices and non-verbally agrees. The team discusses Michael, who chose to go home for Christmas despite the danger posed by his abusive father. Briggs confirms it was Michael’s choice. Cassie deduces Michael is seeking conflict after she chose Dean over him.

Chapter 5 Summary

On the flight to Las Vegas, Agents Briggs and Sterling brief the team on a new case: a serial killer who has murdered three people in three days. The first victim, Alexandra Ruiz, drowned in a casino pool with the number 3213 in henna on her wrist. The second, magician Sylvester Wilde, died in a fire on stage; the number 4558 is branded on his wrist. The third, Eugene Lockhart, was killed with an arrow. The deaths were initially ruled accidental.

Chapter 6 Summary

The murders were connected when investigators found the word tertium, Latin for third, inscribed on the arrow that killed Lockhart. Upon landing, Briggs explains that casino owners requested the FBI’s involvement. As they prepare to disembark, Sloane, a Vegas native, becomes erratic. Lia takes charge to help her, and Judd and Sterling silently approve.

Interlude 1 Summary: “You”

The killer reflects on the number three, recalling he killed the old man with an arrow on the third of January. The act brought no joy and felt less elegant than his first two murders but was a necessary part of his plan. He pockets the arrowhead and wonders if he has finally gotten their attention. Concluding that three victims are not enough, he resolves he cannot stop.

Chapter 7 Summary

As the team arrives at their mediocre hotel, Michael appears and announces he has booked them a luxury suite at the opulent Majesty Resort. At the entrance, Sloane grows anxious, reciting the digits of pi to cope. Inside, the owner’s son, Aaron Shaw, escorts them to a fancy suite. Cassie profiles Aaron’s detached behavior, while Sloane gives answers that are mostly recitations of tangentially related data and facts when he speaks to her. When Aaron asks if she has stayed there before, a shaken Sloane denies it, leaning on Cassie for support.

Chapter 8 Summary

In the suite, Michael reveals his estranged father paid for the rooms, which worries Dean and Cassie. Later, Sloane confides in Cassie that Aaron Shaw is her half-brother and doesn’t know she exists, making Cassie promise to keep her secret. To distract Sloane, Cassie asks for help with the numbers from the murders; the novel reveals that the number on Lockhart’s wrist was 9144. Lia enters and, seeing Cassie’s panicked reaction to a fake claim about her vacation, deduces something difficult happened at home. Before Cassie can respond, Lia announces a visitor.

Chapter 9 Summary

Agent Sterling arrives, annoyed by the high-profile accommodations. Michael defuses the tension by explaining his cover story: He is a spoiled VIP, the team is his entourage, and Judd is his butler. Sterling relents and distributes case materials. As she leaves, she covertly gives Cassie a USB drive containing her mother’s case files. The others witness the exchange, so to deflect curiosity, Cassie directs the team’s focus to the Las Vegas case.

Chapter 10 Summary

The team analyzes the Vegas case files, focusing on five persons of interest: poker players Thomas Wesley, Camille Holt, Daniel de la Cruz, and Beau Donovan, and magician Tory Howard. Lia notes Camille is also a method actress fascinated with trauma. While watching footage of Eugene Lockhart’s murder, Sloane isolates the moment of impact. Michael rewinds, and Dean spots Camille on another feed near the scene, confirming she was present.

Chapter 11 Summary

After six hours, Judd forces the group to take a dinner break. Cassie finds the USB drive and has a flashback to Agent Locke, a killer obsessed with her mother’s murder and the villain of the series’s first novel, The Naturals. Cassie intends to look at the files but stops when she overhears Lia confronting Michael in the hallway, forcing him to reveal fresh bruises from a beating by his father. Cassie retreats to her room, where Dean finds her. Sensing her distress is unrelated to Michael, he gently profiles her. Cassie trusts him and reveals that a body has been found.

Foreword and Chapters 1-11 Analysis

These opening chapters establish the novel’s central thematic conflict by juxtaposing the conventions of biological kinship with a more potent, earned sense of belonging. The exploration of The Redefinition of Family Through Shared Trauma and Trust begins by presenting Cassie’s paternal family as a source of both comfort and isolation. Nonna’s house is filled with the signifiers of a traditional family unit: boisterous arguments, shared meals, and unwavering affection. Yet, within this environment, Cassie is fundamentally unknowable. Her family’s ignorance of her true life—their belief that she “spent the past six months at a government-sponsored gifted program” (4)—renders their love incapable of reaching the most traumatized parts of her identity. In contrast, the bond she shares with the Naturals is predicated on a mutual understanding that transcends verbal communication. Her immediate thought upon receiving the news about her mother is a longing for her teammates, a testament to where she now locates her true support system. This found family operates on a level of gestural comprehension: Judd intuits her need for the case files, Dean recognizes her distress without being told, and even Lia’s abrasive teasing serves a protective function. This dynamic illustrates that true family is not a matter of blood relation but of shared context and experience, creating a chosen unit forged in trauma that provides the necessary psychological foundation for survival.


The narrative also frames the characters’ exceptional abilities as direct consequences of their personal histories, establishing The Relationship Between Talent and Trauma. The skills that make the teens “Naturals” are not presented as gifts but as highly developed survival mechanisms. Cassie’s profiling talent is her primary tool for processing grief and imposing order on the chaos of her mother’s violent death; she compulsively analyzes her family to manage emotional complexity and later dives into the Las Vegas case to forestall her own pain. Dean’s profiling method requires him to inhabit the killer’s perspective by speaking in the first person, a process that forces him to confront his fear of inheriting his serial killer father’s monstrosity. Michael’s emotion-reading, a skill learned to navigate his father’s abuse, is weaponized for control and manipulation, seen when he secures the luxury suite at the Majesty to assert dominance in an effort to soothe his psychological pain. Sloane’s retreat into statistics, especially her recitation of pi when faced with the distressing reality of her family’s casino, is a defense mechanism against overwhelming emotion. This link between talent and trauma makes the characters’ abilities a double-edged sword, providing purpose while simultaneously forcing them to relive the pain that created the skill.


The investigation into the Las Vegas murders connects the motif of games and puzzles to The Inevitable Collapse of Ordered Systems of Violence. The killer’s methodology is a display of intellect, with a number puzzle marked on victims. This mathematical reference frames murder as a structured, intellectual contest—a game of wits between the killer and law enforcement. However, this veneer of cold logic is systematically eroded by the killer’s escalating methods. The crimes devolve from a staged drowning and a complex “accidental” fire to a public murder with a hunting arrow. This progression marks a critical shift in the killer’s psychology, from the detached satisfaction of a puzzle-making to the desperate, emotional need for recognition. The Latin inscription on the third murder weapon, tertium, is not a clue within the game but a direct demand to be seen and understood. The narrative thus posits that even the most rigidly ordered systems of evil are ultimately corrupted by the chaotic personal motivations that drive them.


The novel’s narrative structure, which alternates between Cassie’s third-person limited perspective and the killer’s second-person “You” chapters, mirrors the act of profiling. By restricting the primary viewpoint to Cassie, the story is grounded in her immediate emotional crisis. Simultaneously, the gradual disclosure of her teammates’ traumas reinforces the motifs of secrets and trust. Information is not given freely but is earned through observation, deduction, or moments of intense emotional pressure. The reader learns of Michael’s abuse not from him, but by overhearing Lia’s confrontation. Sloane’s painful family secret is revealed in a moment of acute distress after encountering her half-brother. This fragmented method of characterization transforms the reader into a fellow profiler, piecing together psychological portraits from behavioral clues and guarded confessions. The inclusion of the killer’s “You” chapters heightens this effect, providing direct access to the unidentified subject’s (UNSUB) psyche that creates dramatic irony and allows the reader to see the “game” from both sides, making the stakes feel more immediate.


Key symbolic objects foreshadow the larger conspiracies that lie beneath the surface of the Las Vegas case. Cassie’s mother’s necklace, introduced as proof of her death, represents unresolved conflict. Cassie refuses to accept the necklace as an heirloom or memento; instead, she views it at a professional remove as evidence. This reaction is a refusal of closure, hinting that the official story is incomplete. This object, meant to be an endpoint, instead serves as the catalyst for her renewed investigation. In parallel, the numbered tattoos on the victims function as a symbol of dehumanization and ownership, reducing individuals to data points in the killer’s intellectual pattern. These numbers, initially appearing to be the unique signature of a single killer, are the first indication of a ritualistic system. Their cold, mathematical nature foreshadows the discovery of a society that treats murder as an ordered, generational tradition. Together, these symbols function as cornerstones of the plot, weaving Cassie’s past into her present and transforming a serial killer case into the first move in a much larger game.

blurred text
blurred text
blurred text

Unlock all 56 pages of this Study Guide

Get in-depth, chapter-by-chapter summaries and analysis from our literary experts.

  • Grasp challenging concepts with clear, comprehensive explanations
  • Revisit key plot points and ideas without rereading the book
  • Share impressive insights in classes and book clubs