Jennifer Hillier’s 2020 novel Little Secrets is a psychological thriller that traces Marin and Derek Machado’s emotional responses to their four-year-old son Sebastian Machado’s disappearance. Set in Seattle, Washington, the novel is written from the third-person point of view and alternates between presenting the perspectives of both Marin and Derek’s lover, McKenzie Li.

Sixteen months after Sebastian disappears, Marin and Derek are having marital issues. Marin starts to see a therapist and attends a support group, but she privately has no interest in healing for fear of losing her son forever. Derek also struggles to confront his loss and pursues an affair with 24-year-old McKenzie to distract himself from his grief and guilt. The couple’s secrets drive them further apart and preclude their healing processes. When Marin discovers the truth about Derek’s infidelity, she decides to have McKenzie killed. Meanwhile, McKenzie’s loneliness in her relationships compels her to make irrational decisions. The characters’ increasingly entangled lives inspire the novel’s thematic explorations of Conflict and Loyalty in Intimate Relationships, The Moral Complexities of Revenge, and Identity and Self-Worth After Personal Tragedy.

Little Secrets is a national bestseller and has been nominated for both the Los Angeles Times Book Prize and the Anthony Award. The novel embodies the structure, form, and tropes of the psychological thriller genre while simultaneously offering in-depth examinations of the human psyche.

This guide refers to the 2021 Minotaur Books paperback edition of the novel.

Content Warning: The novel contains references to and depictions of suicide, depression, sexual assault, kidnapping, and dismemberment.

Plot Summary

The novel opens at Pike Place Market in Seattle, Washington, one Saturday afternoon. Marin Machado takes her four-year-old son, Sebastian, to the market for the day to meet her husband, Derek. She gets distracted when her best friend, Sal Palermo, calls, and Derek calls afterward to say he’ll arrive soon. Marin then loses sight of Sebastian. Marin races around the market desperate to find her son. When Derek finally arrives, he blames Marin for what happened.

Marin spirals into depression and despair when Sebastian’s case quickly goes cold. She attempts to die by suicide, and Derek has her admitted to a psychiatric facility. Upon her release, Marin tries to get better. She starts seeing a therapist and attending a support group for parents who have lost their children.

Meanwhile, Marin communicates with Vanessa Castro, the private investigator she hired when the police failed to recover Sebastian. During one of their meetings, Castro informs Marin that Derek is cheating on her. Her contact found Derek with a 24-year-old woman named McKenzie Li while looking into Derek’s colleagues and their potential involvement in Sebastian’s kidnapping. Marin is shocked by this news and resorts to anger.

Marin meets up with Sal at his bar and tells her what she’s discovered about Derek. Sal and Marin have remained friends ever since they broke up years prior. Sal immediately sides with Marin and offers to help her hire someone to kill Derek. Marin decides to use Sal’s contact to have McKenzie killed instead.

McKenzie is a struggling art student who got involved with Derek to garner some semblance of financial stability. She only meant for the relationship to be transactional, but she has fallen for Derek over the course of their relationship. Recently, however, Derek has grown withdrawn and hostile. McKenzie worries that he’s going to break up with her and forget her. She confides in her friend J.R. about her concerns, and he assures her that Derek and Marin won’t last. He’s convinced that McKenzie has a potential future with Derek.

Marin suddenly understands that she shouldn’t have McKenzie killed when the police find the body of her support group friend’s son. She realizes that McKenzie is loved and people will mourn her, too. She calls Sal to call off the hit. However, Castro informs her that McKenzie is missing not long after.

Castro’s investigations into McKenzie’s whereabouts reveal that she is involved with Sal and Sal’s fixer. Castro uncovers the link between them because McKenzie and Sal are from the same hometown. McKenzie has called Sal by his childhood nickname, J.R., since their romantic relationship years prior. Together, Marin and McKenzie realize that Sal was responsible for Sebastian’s kidnapping. Sal wanted to use Sebastian’s disappearance to drive Marin and Derek apart and draw Marin back to him.

Marin shares these revelations with Derek, and Derek opens up to Marin about his own secrets and lies. The couple decides to go to Sal’s farmhouse in the country to confirm their suspicions. Castro joins them. With the help of police and FBI agents, the Machados reunite with Sebastian, who Sal has been keeping in his cellar. In the month following, the Machado family pursues healing together. Marin also makes amends with McKenzie, who she knows she has wronged.