Publication Date: August 4, 2026
In 1926, five women disappeared from a remote island in Vermont. Now, one hundred years later, it’s happening again.
Struggling actress Marin Keane is shocked when she lands a role in a major motion picture about the unsolved mystery of New Avalon, an island on sprawling Lake Faraday in Vermont. She’s even more surprised when she learns that the role requires a weeklong research trip to that very spot.
Because New Avalon isn’t your ordinary island. A century ago, it was a commune for spiritual mediums-until they all vanished in 1926. The only trace of them was five dresses hanging from the branches of an old oak tree in the middle of the island, one for each missing woman. Some locals say they simply left. Others think they were murdered. But the prevailing opinion, thanks to a diary left behind by one of the vanished, a young woman named Daisy Rue, is that a séance gone wrong conjured something supernatural that took them all one by one.
Not long after arriving, Marin and her castmates, including legendary actress Violet Wright and white-hot director Ronan Peters, begin to realize all is not right with New Avalon. They hear strange noises in the night and notice mysterious symbols left behind by the island’s previous occupants. And after a sudden health emergency leaves Marin, Ronan, and the other actors stranded on the island, the disappearances begin again.
Is it the work of someone trying to derail the movie? Or is the island’s alleged supernatural past catching up with the present? As fear and suspicion mount, Marin turns to Daisy’s diary, hoping it holds the key to figuring out what really happened to the women of New Avalon-and how to keep the island’s terrible history from repeating itself.
A fledgling actress lands an unexpected role that propels her straight into danger.
Author Riley Sager delivers a spooky tale in The Unknown. The premise seems deceptively simple. Marin Keane joins her castmates for a week-long character immersion adventure on an island near Vermont.
To get into character, everything is designed to mirror 1926, from the clothes they wear to the lack of modern conveniences. Little does Marin realize there is a specific reason why the trip is set on New Avalon.
The movie showcases the mysterious disappearance of five women through the lens of a diary written by the character Marin is to play. The author does a phenomenal job building suspense as different theories are tossed around.
However, when reality starts mimicking the past and castmates disappear, Marin finds herself searching Daisy’s diaries for help. Someone—or something—is wreaking havoc on the island.
The Unknown combines solid character development with a thrilling mystery guaranteed to generate goosebumps.
Riley Sager is the New York Times bestselling author of nine novels, most recently Middle of the Night and The Only One Left. His books have been published in over 35 countries, with more than 3 million copies sold worldwide. His latest book, With a Vengeance, will be published in 2025 by Dutton Books.
A native of Pennsylvania, he now lives in Princeton, New Jersey.
