Warning: This post contains spoilers for The Woman in Cabin 10.On her first night on board the Aurora Borealis, a luxury superyacht embarking on a weeklong maiden voyage across the North Sea, journalist Laura “Lo” Blacklock (Keira Knightley) witnesses the aftermath of a passenger being thrown overboard from the balcony of the cabin next to hers. But when she’s told all the guests and crew have been accounted for after reporting the incident, she begins to realize someone on the ship is harboring a dark secret. Therein lies the whodunnit crux of Netflix’s new psychological thriller The Woman in Cabin 10. [time-brightcove not-tgx=”true”]The Aurora Borealis is owned by billionaire Anne Lyngstad (Lisa Loven Kongsli), a Norwegian shipping heiress with stage 4 leukemia, and her husband, Richard Bullmer (Guy Pearce), and is en route to Norway for a fundraising gala organized to support the launch of the couple’s new cancer research foundation. Lo, along with her photographer ex-boyfriend Ben Morgan (David Ajala), were invited to join the foundation’s board members on the cruise in order to publicize the charitable endeavor. But the perpetrator of the crime clearly didn’t count on Lo putting her investigative talents to work against them.The Woman in Cabin 10 is based on Ruth Ware’s best-selling 2016 novel of the same name and follows Lo as she fights to uncover the truth about what happened that night amid escalating threats to her safety. Directed and co-written by Simon Stone (The Daughter, The Dig), the movie takes some creative liberties with its source material, but keeps with the book’s central theme of what Ware has described as “the fear of not being believed.”“Cabin 10, at its heart, is about a woman who experiences something wrong, reports it truthfully, and isn’t taken seriously because of who she is,” the author told Netflix’s Tudum. “Too many people know what that feels like and I think we want vindication for ourselves as much as Lo.”Who was thrown overboard in The Woman in Cabin 10?Whoever was behind the murder is willing to go to pretty much any length to keep their identity from being revealed—at one point, someone pushes the questioning Lo into the yacht’s pool, causing her to nearly drown. But that night, Lo gets a big break in the case when she hears a knock on her door, pursues the unexpected visitor through the bowels of the ship, and comes face to face with the same blonde woman she briefly encountered that first evening in cabin 10 and later spotted in a photo Ben had taken months earlier at one of the group’s parties.The woman begs Lo to stop her investigation, insisting that “he” will kill her if she doesn’t. But when Lo grabs at her hoodie it pulls off the woman’s blonde wig to reveal it’s a heavily made-up Anne…or is it? After the woman knocks Lo out and locks her in a bunker below deck, she eventually returns and reveals what really happened that night. As it turns out, it was actually Anne who was thrown overboard by Richard after he recruited the blonde woman, Carrie (Gitte Witt), to replace her. Richard had been searching for a passable lookalike for Anne since learning she was planning to disinherit him and give all their money to the foundation when she died, and he had found Carrie using an AI-powered facial recognition software invented by one of the foundation’s board members.Carrie tells Lo she was only meant to pretend to be Anne for one day in order to meet with her lawyers and amend her will to Richard’s benefit. But when Anne walked in on Richard kissing Carrie—who had just finished shaving her head and disguising herself—she, quite understandably, freaked out, and the couple got in a scuffle that ended with Richard chucking Anne into a bureau so hard it cracked her skull. Much to Carrie’s dismay, he then tossed Anne’s body overboard and attempted to rid the room of any evidence.Carrie tells Lo that she only did all this to earn enough money to give her daughter a good life, but never thought it would lead to murder. But Lo counters with the obvious point that Richard isn’t going to leave any loose ends lying around by letting Carrie live after she’s finished signing the new will.That night, Carrie overhears Richard and Anne’s doctor Dr. Mehti (Art Malik) discussing how they had originally planned for Mehti to give Anne an overdose in order to kill her. Richard then uses this to blackmail Mehti into agreeing to kill Lo once they find her. When Carrie returns to the bunker, she tells Lo she will leave the door open so Lo can escape when everyone goes ashore for the gala. How does the movie end?When Lo emerges from the bunker, she sneaks into the ship’s library and retrieves the gala speech the real Anne asked her to read on the first night announcing her plan to give all her money away. Mehta and Richard’s other accomplice, Captain Addis (John Macmillan), then attack and attempt to kill Lo. But Ben, who stayed behind to make sure Lo was OK, ends up saving her. Unfortunately, in the process, he’s stabbed by the syringe Mehta intended for Lo and dies. Lo then jumps overboard to escape the assault and swims through the freezing waters to shore. Lo makes her way to the compound where the gala is being held and encounters Sigrid (Amanda Collin), Richard and Anne’s head of security. By showing her the speech, she’s able to convince Sigrid, who has noticed some strange behavior, to let her follow through with her plan to storm the stage at the gala that night and prove what she’s saying is true. At the gala, once Richard’s crimes are revealed in front of the crowd, he puts a knife to Carrie’s throat and drags her down to the dock in an escape attempt. Luckily, Sigrid is able to shoot Richard in the shoulder with a gun she’s retrieved in the nick of time, and Lo manages to finish him off by hitting him over the head with a metal pipe. Teamwork.An epilogue sequence shows Lo has returned to work and written a story about the whole ordeal focused on Anne’s contributions to cancer research. The piece reveals that Mehta and Addis are set to stand trial for their roles in the double murder of Anne and Ben. Lo then receives a video message from Carrie showing her daughter playing and inviting Lo to come visit them.