After last year’s With a Vengeance, a nod to the golden age of mysteries, Riley Sager has returned to form with The Unknown. Sager does best with atmospheric thrillers, whether it’s a haunted house (Home After Dark), a creepy historic apartment for the elite (Lock Every Door), or a crumbling mansion by the sea (The Only One Left).
This time, the setting is an island off the coast of Vermont, where the cast members of a hot director’s latest project–based on the true story of the disappearance of five women in 1926–are expected to slip into their characters by living and dressing exactly as the ill-fated group did for a week. Sager takes advantage of every element at his disposal, ratcheting the tension one notch at a time while combining a foreboding sense of doom with the sexiness of Hollywood.
Unknown actress Marin Keane enters her audition as a last-minute replacement in a new film with no expectations. Considering her biggest role to date is as “bridesmaid with a rash,” Marin doesn’t expect to win a part that will put her opposite screen legend Violent White. Perhaps this is why, when hot young director Ronan Peters tells her to “tell him a ghost story,” she does so without inhibition and lands herself the part. Marion will receive her Screen Actors Guild card and a hundred thousand dollars in exchange for a part that could make her a star.
The mystery is what, exactly, this part is. Marion knows Ronan’s latest effort will tell the story of the five women who disappeared from the remote island, but further details are scant. She arrives on the island, relinquishes her phone as instructed, and is finally provided the script for the table read. And she realizes that Violet Wright isn’t the star. The actress playing the character of “Daisy” is. That’s Marion.
Desperate not to fail at this chance of a lifetime, Marion vows to become Daisy, to be worthy of this opportunity. With the exception of Susie, a former Disney star who isn’t nearly as sugary-sweet as she appeared on the small screen, the other actresses are kind. Violet Wright may be larger than life, but she’s human and empathetic when she bonds with Marion over pilfered liquor, And Ronan is patient and nurturing as a director, providing Marion with a copy of the real Daisy’s actual diary as found on the island and complimenting her raw talent.
But something’s not right. No one ever discovered what happened to the five women who had disappeared from the island. Daisy’s diary weaves a story of being taken in by a woman who used the island–inherited by a relative who earned his money through questionable means–as a place of refuge for women with extraordinary abilities. An orphan, Daisy was grateful for the sense of community, but soon the diary speaks of events that can only be explained by a supernatural presence. And, during a seance, the women found themselves confronted by a dark presence that whispered to Daisy, “you will be last.” True to the wraith’s word, the other women began disappearing one by one, their clothing left hanging in a massive oak tree.
While Marion doesn’t want to believe Daisy’s diary, she can’t ignore her impending sense of door. From the odd symbols carved in the trees to the scratching in her cabin at night, it doesn’t feel like she and the crew are alone. And then, during a seance simulated to resemble the one that occurred a century ago, it seems that Marion and the others have again invited in a spirit that wishes harm to the island’s inhabitants. Thanks to a medical emergency that resulted in the production crew leaving the island–inadvertently taking the bag of confiscated phones–there’s no escape route. And history begins to repeat itself.
The Unknown executes a fun concept well. This isn’t the first time we’ve seen this plot–Scream 3, anyone?– but as we know with any good horror movie or thriller book, the success or failure is in the implementation and the elements. Sager teases us with several plot points–the dual mysteries, Marion’s backstory, the fate of the production–all of which are enticing enough to flip the pages. We love a dangling carrot.
The story, does, however, has the most momentum in the first half, propelled by the irresistibly creepy tone and build-up. Parts of the ending climax and resolution feel rushed, especially considering the masterful storytelling job and set-up in the beginning. And while Marion’s not the female lead running up the stairs when she should be running out the front door; some of her reactions are hard to understand. Still, it’s not enough to jar the reader from the world Sager has created. Bring this one to any lake house or cabin and read under the covers long after everyone else has gone to sleep.
The Unknown by Riley Sager
Dutton/August 4, 2026
