There is a particular pleasure in a Riley Sager novel that arrives with the season’s first cold front. You sense the setup before the second chapter ends. An isolated location. A clever woman in over her head. A history that refuses to stay buried. The Unknown by Riley Sager honors that contract, then quietly tilts it sideways. What starts as a gothic ghost story turns into something stranger by the final third, with one foot in the séance parlor and the other on a movie set.
Marin Keane is a barely working actress when she lands a part in a horror film about New Avalon, an island on Vermont’s Lake Faraday where five spiritualists vanished in 1926. The director is Ronan Peters, a method obsessive with movie-star looks and a controlling streak. The star is Violet Wright, an Oscar winner whose presence makes Marin feel like a fraud the moment she steps off the boat. The role demands a week of research on the island itself, in 1920s clothes, sleeping in the same cottages where the missing women slept. Then, of course, the disappearances start again.
A Setting That Earns Its Goosebumps
Atmosphere is where The Unknown by Riley Sager shows its hand first, and it shows it well. New Avalon is small enough to map but large enough to lose someone in. There is an oak tree at its center where the five empty dresses once hung. There is a parlor that still smells of melted wax and a sideboard with a wicker-fronted box that Marin keeps returning to. Fog rolls in. Phones lose signal. A boat goes missing in the night.
Sager has always understood how to use a confined space as both stage and trap, and here the island is the most disciplined character in the book. Every creaking floorboard pays off later. Every drawer that doesn’t quite close becomes a problem in chapter twenty.
Two Voices, One Mystery
Structurally, the novel runs two timelines side by side. Marin’s modern chapters carry the propulsive first-person voice Sager fans know well. Threaded between them are entries from a 1926 diary by Daisy Rue, one of the vanished women. Daisy’s prose is mannered, period-accurate in its rhythms, peppered with talk of “the Gift” and “the Darkness.” For the most part the diary works as a slow-burn counterweight to the modern chaos, and the way the two timelines start to mirror each other is the engine of the book’s middle third.
A Cast That Behaves Like Real Actors
Marin is a sharply observed lead. She is plain by Hollywood standards, broke, conscious of every social rung above her, and just bitter enough to be funny. Her self-deprecation never tips into pity. Violet Wright, all calculated warmth and tactical silences, is a genuinely interesting creation. The supporting players (the costumer, the second lead, the assistant director with too many opinions) round things out, though a few of them function more as suspects to rotate than as people you remember.
What This Book Gets Right
A few things separate The Unknown by Riley Sager from a hundred other locked-island thrillers on the shelf:
- A genre handshake that pulls horror, historical fiction, and crime fiction into the same room without picking a fight between them
- A diary device that contributes actual plot mechanics, not just mood
- Smart commentary on method directing, the ethics of immersive art, and the kinds of people who climb the Hollywood ladder
- A morally slippery final act that resists the tidy heroism a lot of thrillers default to
- Reliable, propulsive pacing in the second half once the séances begin in earnest
The séance scenes are especially good. Sager stages them with theatrical timing, breaks them with cynical observation, then lets them tip into something that might or might not be real. It is a confident piece of craft.
Where It Stumbles
Honest critique earns its place here, because the book is not flawless. The Unknown by Riley Sager has a few visible seams that experienced thriller readers will spot:
- A pair of mid-book twists are signposted heavily enough that they feel more confirmed than revealed
- The diary voice occasionally drifts from period-appropriate into period-pastiche, especially in early entries
- The ensemble is large, and at least two of the supporting cast members feel like names on a call sheet rather than full characters
- The supernatural ambiguity, which is the book’s most interesting choice, gets undercut by an epilogue that explains a little more than it needed to
- The final reveal of what really happened in 1926 will satisfy some readers and frustrate others, depending on how much they value clean closure
None of these are fatal. They are the visible scaffolding of a writer who has now published ten novels and knows exactly where readers expect a turn, and occasionally gives them that turn a beat early.
Sager Still Writes Like Sager
For anyone who has read Home Before Dark, The Last Time I Lied, or The Only One Left, the DNA is familiar. Sentences run short. Chapters end on a hook. The first-person narrator is wry and a touch unreliable. This entry leans further into horror than With a Vengeance and further into gothic than Middle of the Night, while sitting comfortably next to The House Across the Lake in tone. Returning fans will feel at home. Newcomers can start here without missing anything.
If You Liked This, Try These Next
Readers who finish The Unknown by Riley Sager and want more of the same atmosphere should reach for:
- The Sun Down Motel by Simone St. James, for the dual-timeline supernatural mystery built around vanished women
- The Drowning Kind by Jennifer McMahon, for the haunted-water-in-rural-New-England energy
- The Death of Mrs. Westaway by Ruth Ware, for the séance-adjacent gothic with a sharp narrator
- Mexican Gothic by Silvia Moreno-Garcia, for the isolated house, lurking presence, and slow paranoia
- The Hunting Party by Lucy Foley, for the closed-circle cast picked off one by one
- The Winter People by Jennifer McMahon, for the diary device folded into a present-day reckoning
- And Then There Were None by Agatha Christie, the foundational text this novel is in clear conversation with
Worth the Ticket Price
By the time the credits roll on The Unknown by Riley Sager, you will probably have guessed one of its secrets and missed the other two. It is a confident, satisfying thriller from a writer doing what he does best, with enough genre crossover to feel fresh and enough small wobbles to feel honest. Read it during a thunderstorm, ideally near a lake, ideally not alone.