The Unknown
One hundred years ago, five women vanished without a trace from New Avalon, a remote island commune for spiritual mediums. Their only legacy: five dresses hanging from an old oak tree, and a terrifying diary hinting at a séance gone wrong, conjuring something unspeakable. Now, history threatens to repeat itself.
Struggling actress Marin Keane thinks she’s hit the big time, cast in a movie exploring New Avalon’s chilling mystery. But her dream role quickly becomes a nightmare when the production demands a weeklong research trip to the very island where the original disappearances occurred.
Alongside legendary actress Violet Wright and acclaimed director Ronan Peters, Marin soon discovers New Avalon is far from dormant. Strange sounds echo in the night, cryptic symbols appear, and then, a sudden crisis leaves them all stranded. As the lines between past and present blur, the disappearances begin anew.
Is a saboteur stalking the set, or has the island’s dark past awakened? Marin must race against time, delving into Daisy Rue’s century-old diary to unlock the island’s secrets before she, too, becomes another victim of The Unknown.
- Marin - Actress playing Daisy
- Loretta - Producer, Violet’s sister
- Brad - Production assistant
- Ronan - Director
- Pete - Boat captain
- Julianne - Actress playing Phoebe
- Dean - Julianne’s husband, deceased
- Violet - Actress playing Ruth, Loretta’s sister
- Heather - Actress playing Jonquil
- Susie - Actress playing Katrina
- Lindy - Actress originally playing Daisy
- Molly - Marin’s sister, deceased
- Ruth (Mrs. Semple) - Owner of New Avalon
- Katrina - Figment of Azra’s psychosis
- Jonquil - Figment of Azra’s psychosis
- Phoebe (Mrs. Minafer) - Figment of Azra’s psychosis
- Daisy/Azra - Guest on New Avalon
- Roderick Semple - Ruth’s father, industrialist
- Mr. Ruggle - Pete’s grandfather
- Elise - Actress, Violet’s daughter deceased
- Ronan is directing a horror movie starring Violet and casts Marin in a role at the last minute after the original actress is fired.
- The movie is about New Avalon, an island where Mrs. Ruth Semple spent summers with other women until they disappeared in 1926, leaving only five dresses hanging from an oak tree.
- Daisy’s diary spoke about how the women performed seances on the island until they summoned an evil entity named Azra.
- Pete, Ronan, Brad and the cast travel to New Avalon so the actresses can live like their characters for five days.
- The island has four small cottages and one large house.
- Ronan gives Marin a copy of Daisy’s diary which the film is based on.
- Daisy’s Diary: The women have a seance and contact a spirit named Azra.
- The actresses perform a seance and summon Azra.
- Brad has a medical emergency and Loretta takes him in a boat to the mainland.
- Daisy’s Diary: Katrina goes missing and her clothes are found hanging in the oak tree.
- Marin dreams that she sees Molly outside her cottage.
- Susie disappears and her clothes are found hanging in the oak tree.
- Violet and Marin find a camcorder on an alter in the woods.
- On the camcorder is a video of Susie being attacked in the woods.
- Daisy’s Diary: Mrs. Semple allows a bootlegger to use her island. The bootlegger drops off crates of booze, and Mr. Ruggle picks them up when he delivers groceries.
- It was Loretta’s idea to come to New Avalon, not Ronan’s.
- Heather goes missing and her dress is hanging from the oak tree.
- Daisy’s Diary: Daisy dreams that Azra slashes Jonquil’s throat.
- When Marin was four and Molly was eleven, Molly drowned in their backyard pool.
- Marin feels guilty over Molly’s death, thinking that if she had gone outside when Molly went swimming, she wouldn’t have died.
- Julianne disappears.
- Marin thinks she sees Molly outside her window but realizes it is Susie and chases her into the woods, where she finds Julianne and Heather as well.
- Violet admits that everything that happened on the island was fake and that she, Julianne, Susie and Heather planned it all.
- Elise killed herself after learning that Ronan secretly recorded them having sex and shared the video with others.
- Violet and the other actresses planned the trip to New Avalon to scare Ronan into admitting that he was responsible for Elise’s death.
- When Lindy found out about the plan, she didn’t want to be involved, so Loretta fired her.
- Marin finds the final pages of Daisy’s diary hiding behind a baseboard in her cabin.
- Daisy’s Diary: Daisy stabs Mrs. Semple to death.
- Ronan, Violet and Marin hold a seance.
- During the seance, Violet pretends to be possessed by Daisy, gets Ronan to admit what he did to Elise and then stabs him with an ice pick.
- Violet and Marin throw Ronan’s body off a cliff.
- Marin finds Mrs. Semple’s skeleton and diary underneath the floorboards of Daisy’s cabin.
- Mrs. Semple’s diary: New Avalon was a place where women went to receive psychological help, not a retreat for mediums and witches.
- Mrs. Semple went to prison to meet a young woman who killed her father. Daisy introduced herself, and Mrs. Semple took her back to New Avalon to evaluate her and determine whether she was mentally ill. Katrina, Jonquil and Mrs. Minafer were figments of Daisy’s imagination, and Daisy’s real name was Azra.
- Azra suffered from paranoid schizophrenia and multiple personality disorder, Daisy was her alter personality.
- Elise was Violet’s daughter, whom she gave up for adoption after having an affair with a married director.
- Marin tells Violet she will go to the police about Ronan’s murder unless Violet helps make her famous.
- Four years later: Authorities believe that Ronan accidentally fell to his death on New Avalon.
- Marin is a successful Hollywood actress.
- Marin finds a photograph of a woman named Zara who is the spitting image of Azra. Zara was married to a businessman who made a lot of money ferrying booze to America during Prohibition.
Riley Sager knows how to build an atmosphere that keeps you on edge, and the setting of New Avalon - a small, isolated island off the coast of Vermont - gives this story a distinctly creepy, supernatural edge. The narrative unfolds through medium-length chapters from Marin’s point of view in the present, interspersed with entries from Daisy’s diary written a century earlier. While I found myself rooting hard for Daisy and looking forward to her perspective, Marin felt a bit too naive to fully get behind. The structure also hits a pacing snag because Marin’s present-day actions mirror the diary so closely that you end up reading about the same beats twice.
The momentum recovers once the twists start hitting. A few sharp revelations completely changed how I viewed the entire premise, turning that initial repetition into a much cleverer setup. What impressed me most was how so many small, seemingly throwaway details from early on ended up mattering later - things that felt insignificant in the moment came together seamlessly by the climax. The resolution strikes a great balance, answering the core questions while leaving just enough lingering ambiguity to keep you thinking about it afterward.
If you like dual-timeline mysteries, isolated island settings, and supernatural-tinged suspense, then you will enjoy this book.
- Molly - Dead - Drowned
- Elise - Dead - Committed suicide
- Ronan - Dead - Stabbed to death by Violet
- Mrs. Ruth Semple - Dead - Killed by Azra
- Katrina - A figment of Daisy’s psychosis
- Jonquil - A figment of Daisy’s psychosis
- Mrs. Minafer - A figment of Daisy’s psychosis
- Susie - Alive - Still acting
- Heather - Alive - Still acting
- Julianne - Alive - Still acting
- Violet - Alive - Still acting
- Marin - Alive - Has become a famous actress
- Daisy/Azra - Suspected to have escaped the island with a bootlegger
- Death
- Suicide
- Grooming
- Rape
- Murder
- Blackmail
Publisher: Dutton
ISBN: 9798217044092
Publication Date: August 4, 2026
Note: Details are for the original edition. Other formats, editions, and audiobook versions may be available.
