Lo Blacklock, a travel journalist for Velocity magazine, is given the rare opportunity to cover the maiden voyage of the Aurora Borealis, a small, high-end cruise ship designed to accommodate only a select number of elite passengers. This assignment comes at a crucial time for Lo, who has recently suffered a traumatic home invasion that has left her emotionally shaken and dealing with anxiety and insomnia. Hoping the trip will provide a much-needed escape, she boards the ship, eager to experience the luxury and exclusivity it promises.

The Aurora Borealis is designed to provide an intimate and opulent experience for its guests, with only ten cabins and a limited number of passengers. Among them are wealthy businesspeople, journalists, and the ship’s enigmatic owner, Richard Bullmer, who is accompanied by his ill wife. Lo is assigned to Cabin 9, but shortly after settling in, she has a brief interaction with a woman in Cabin 10, who lends her mascara when Lo forgets hers. Later that night, Lo is jolted awake by a loud splash coming from the direction of Cabin 10. Rushing to the balcony, she is convinced she sees a body plunging into the dark waters below.

Disturbed by what she witnessed, Lo reports the incident to the ship’s crew, but she is met with skepticism. When the staff check Cabin 10, they find no sign of a guest, and according to the passenger list, the cabin was never occupied. The mascara that the woman had given Lo is also missing. Struggling with her anxiety, Lo begins to doubt herself, wondering if the stress of recent events has compromised her judgment. But deep down, she knows what she saw, and she becomes determined to prove that the woman existed—and that she was murdered.

As Lo investigates further, she meets the other passengers and tries to piece together what happened. She grows increasingly uneasy as she realizes that there are secrets hidden beneath the ship’s polished exterior. The other guests seem either indifferent or unwilling to acknowledge anything unusual, and she begins receiving cryptic warnings to stop digging. Despite this, Lo presses on, desperate to find evidence that will validate her suspicions.

Tension escalates when Lo’s belongings are tampered with, and she wakes up to find a message scrawled on her mirror warning her to back off. She confides in an old acquaintance, journalist Ben Howard, who is also aboard the ship, but even he doubts her claims. Lo starts to feel isolated, unsure of who she can trust. She begins to suspect that someone on the ship is deliberately trying to silence her, and as she delves deeper, she realizes she may be in grave danger.

Lo’s investigation leads her to discover that Richard Bullmer’s sickly wife, Anne, has not been seen on the ship since the beginning of the voyage. As she pieces together clues, she becomes convinced that the woman in Cabin 10 was Anne—or someone who knew too much. When Lo finally finds solid proof that the woman existed, she is attacked and locked away in a small, dark compartment. Held captive, she is forced to confront the terrifying reality that she may never leave the ship alive.

Determined to escape, Lo uses her wit and resourcefulness to outmaneuver her captors. She learns that Richard Bullmer had orchestrated his wife’s murder to gain control of her fortune, and he had arranged for a woman to impersonate Anne in the days leading up to the voyage. When the imposter grew uneasy and threatened to expose the scheme, she was killed and thrown overboard. Lo’s persistence in uncovering the truth had made her a liability.

In a heart-pounding climax, Lo manages to escape her confinement and signals for help. The ship docks, and authorities become involved, but Richard Bullmer attempts to evade justice. In the aftermath, Lo struggles to process the ordeal, but she ultimately emerges stronger, determined to reclaim her life.

The Woman in Cabin 10 is a masterfully written psychological thriller that keeps readers gripped from start to finish. It explores themes of trust, paranoia, and resilience, making it a compelling and suspenseful read.