The Woman in Cabin 10

The blonde woman was Carrie, a woman Richard Bullmer had hired to impersonate his wife Anne. Richard orchestrated this identity swap so Carrie could sign over Anne's fortune to him. Carrie's appearance in Cabin 10 was part of Richard's scheme to control the situation while Anne was still alive.

Lo first encounters this mysterious blonde woman on her first night when she slips into Cabin 10 to avoid her ex Ben.

Richard murdered Anne because she discovered him kissing Carrie, the woman he had hired to impersonate her. Anne had stopped taking her medication and planned to announce at the gala that Richard would be cut off from her fortune. To prevent this and secure the inheritance, Richard killed Anne and dumped her body overboard.

Anne's private confession to Lo about stopping her medication and her intention to reveal a major financial decision foreshadows the motive for her murder.

Cabin 10 appeared empty because the woman Lo saw was Carrie impersonating Anne. Richard had arranged for Carrie to stay in the cabin under the guise of being Anne, making it seem like the cabin was occupied by the real Anne. When passengers were accounted for, everyone believed Anne was safely in her cabin, not realizing Carrie was there in her place.

Lo finding blonde hair in Cabin 10's sink and later discovering evidence of someone using that cabin points to the deception.

Richard hired Carrie to impersonate Anne so she could sign legal documents transferring Anne's fortune to Richard. After Anne was murdered, Carrie, posing as Anne, would sign a revised will at the gala. This elaborate scheme would have worked if Lo hadn't uncovered the truth and exposed Richard during the public event.

Anne giving Lo a copy of her gala speech about a monumental fortune shift hints at what Richard was trying to prevent.

Ben was killed when he tried to save Lo from Mehta and the captain. After the other guests disembarked in Norway, Mehta and the compromised captain cornered Lo. Ben arrived to help her but was jabbed with a lethal injection by Mehta. Lo then jumped overboard to escape, leaving Ben's fate sealed.

Lo's earlier concern for Ben's safety and the growing danger on the ship foreshadows this tragic outcome.

No one believed Lo because Richard had orchestrated the situation to make her appear unreliable. The ship's security cameras had been deactivated for privacy, eliminating visual evidence. When the passengers were accounted for and no one was missing, Richard used Lo's recent trauma recovery to dismiss her claims as paranoia. Both the crew and guests chose to suspend disbelief rather than investigate.

The spa message "STOP" appearing on Lo's shower door and her room being searched suggest someone is actively undermining her credibility.

Dr. Mehta was Anne's personal physician and was either coerced or paid to assist Richard in his scheme. Mehta participated in the cover-up, helped search for Lo after her near-drowning, and was ordered by Richard to locate and kill Lo. After Anne's murder, Mehta continued to protect Richard's interests aboard the yacht, ultimately killing Ben and planning to eliminate Lo.

Mehta being found missing a button after Lo's near-drowning incident links him to the earlier attack.

Lo survived by swimming toward shore from the yacht despite the freezing Norwegian waters. Though Mehta falsely claimed she couldn't have survived, Lo's determination and swimming ability allowed her to reach land. She then used her journalist skills to orchestrate her return to the gala where she could expose Richard's crimes.

The intense cold of the Norwegian voyage setting establishes the danger Lo faces during her escape.

Lo interrupted Richard during the gala, and with Carrie's quiet support, read Anne's original speech that revealed Richard was being cut off from her fortune. This public revelation exposed his motive for murder. Richard then tried to flee with Carrie as hostage, but Nilssen shot him and Lo struck the final blow.

Anne's earlier gift of her speech copy to Lo foreshadows this climactic moment where the truth is finally revealed.

The evidence Lo found, including blonde hair from the sink and a mysterious button, disappeared after her coat was laundered. This was part of Richard's effort to eliminate proof of the crime. However, Lo had hidden some evidence in her own cabin, and the missing button from Dr. Mehta's coat later became a key clue connecting him to the attack on her.

Lo noticing a missing button on Mehta's coat directly links the doctor to her earlier assault.

Carrie helped Lo because she realized Richard would kill her once she served her purpose. After signing the revised will, Richard would no longer need her silence. Carrie overheard Richard ordering Mehta to kill Lo, which confirmed her own danger. Her daughter was her motivation to break free from Richard's control and cooperate with Lo.

Lo's warning that Richard would kill Carrie after she signed the will plants the seed for Carrie's betrayal.

Sigrid Nilssen was Anne's bodyguard. She became suspicious when Carrie, posing as Anne, signed the revised will. During the gala confrontation, Nilssen retrieved a rifle and shot Richard in the shoulder, disabling him before Lo delivered the final blow. Her loyalty to Anne ultimately helped stop Richard's scheme.

Nilssen's suspicion when reviewing the will paperwork provides the setup for her crucial action during the climax.