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Whereabouts Unknown: A Nadia Cole Thriller - The Horizon Cases Book 2
Not yet published
Expected 15 Nov 26Some children don't run. The system just stops looking.
Nadia Cole is sent to check on six-year-old Devon. In a cold apartment, he shows her a drawing of his mother asleep and himself beside her, "waiting for her to be up." Nadia wants to keep him home, but one more bad night and the county has a clean bed ready.
That bed is in a group home thirteen-year-old Kayla Dunlap vanished from six weeks ago. Her file reads whereabouts unknown, and nobody is looking. To Nadia, the paperwork is too clean, and clean is how you lose a child. At the home, a girl on the stairs whispers that the boy before Kayla never ran away at all.
The case takes Nadia back ten years, to a girl of eight she argued into a group home, written off in one word: absconded. Nadia always told herself the girl ran. Believing it kept her going.
Nadia was wrong.
Then Devon is left alone after dark, and the placement desk offers that bed: "One call and he's placed." Nadia can sign him onto a cousin's couch, risking her job, or make the call and send Devon into the house Kayla vanished from.
An urgent psychological thriller about the missing children a system stops looking for, the cost of a closed file, and a caseworker haunted by the girl she got wrong.
Whereabouts Unknown is Book Two of The Horizon Cases series.
Nadia Cole is sent to check on six-year-old Devon. In a cold apartment, he shows her a drawing of his mother asleep and himself beside her, "waiting for her to be up." Nadia wants to keep him home, but one more bad night and the county has a clean bed ready.
That bed is in a group home thirteen-year-old Kayla Dunlap vanished from six weeks ago. Her file reads whereabouts unknown, and nobody is looking. To Nadia, the paperwork is too clean, and clean is how you lose a child. At the home, a girl on the stairs whispers that the boy before Kayla never ran away at all.
The case takes Nadia back ten years, to a girl of eight she argued into a group home, written off in one word: absconded. Nadia always told herself the girl ran. Believing it kept her going.
Nadia was wrong.
Then Devon is left alone after dark, and the placement desk offers that bed: "One call and he's placed." Nadia can sign him onto a cousin's couch, risking her job, or make the call and send Devon into the house Kayla vanished from.
An urgent psychological thriller about the missing children a system stops looking for, the cost of a closed file, and a caseworker haunted by the girl she got wrong.
Whereabouts Unknown is Book Two of The Horizon Cases series.
283 pages, Kindle Edition
Expected publication November 15, 2026
About the author
A.R. Hollowell
21 books111 followersA.R. Hollowell is the author of psychological thrillers that explore the moral pressure points of ordinary lives. His novels place readers inside impossible choices, not simply to frighten them, but to leave them asking the more unsettling question: what would I have done?
His work lives in the uneasy space between what is legal and what is right. He writes about people caught inside institutions built to protect them, including courts, hospitals, families, workplaces, and systems of authority, where truth is often incomplete and every available choice comes with a consequence. His characters are rarely given clean answers. Instead, they must confront loyalty, guilt, power, grief, responsibility, and the private cost of doing what they believe is right.
Known for atmospheric suspense, emotional complexity, and ethical dilemmas that continue beyond the final page, Hollowell’s stories blend psychological tension with questions of conscience. Whether the threat comes from a hidden past, a professional system, or the person closest to the protagonist, his novels ask readers to look beyond the obvious and consider the human consequences of silence, certainty, and survival.
When he is not writing, A.R. enjoys flying drones, building new things, exploring emerging technology, and watching movies with his family.
Readers can follow A.R. Hollowell and join the Hollowell Circle of Trust Facebook group for new releases, bonus chapters, behind-the-scenes updates, and conversations about the stories still to come.
His work lives in the uneasy space between what is legal and what is right. He writes about people caught inside institutions built to protect them, including courts, hospitals, families, workplaces, and systems of authority, where truth is often incomplete and every available choice comes with a consequence. His characters are rarely given clean answers. Instead, they must confront loyalty, guilt, power, grief, responsibility, and the private cost of doing what they believe is right.
Known for atmospheric suspense, emotional complexity, and ethical dilemmas that continue beyond the final page, Hollowell’s stories blend psychological tension with questions of conscience. Whether the threat comes from a hidden past, a professional system, or the person closest to the protagonist, his novels ask readers to look beyond the obvious and consider the human consequences of silence, certainty, and survival.
When he is not writing, A.R. enjoys flying drones, building new things, exploring emerging technology, and watching movies with his family.
Readers can follow A.R. Hollowell and join the Hollowell Circle of Trust Facebook group for new releases, bonus chapters, behind-the-scenes updates, and conversations about the stories still to come.
Ratings & Reviews
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Displaying 1 - 7 of 7 reviews
Review of advance copy
I was fortunate to receive an ARC copy of Whereabouts Unknown & am leaving this review voluntarily. Right from the start of this book I was intrigued, it was almost impossible to put down! A.R Hollowell has a wonderful way of portraying characters dealing with difficult situations. He makes you question what you would do in their situation constantly throughout this book. Whereabouts unknown had me emotionally invested from very early on, it made me feel so many emotions that varied throughout the book! Another 5 star read! Well done, cannot wait for your next book :)
Review of advance copy
Received as an ARC through Booksirens to read and review, this is an honest review.
Author A.R. Hollowell writes breathtaking dangerous stories that don't sugarcoat the tough conversations these stories invoke.
That's the point. We need these emotional stories.
Nadia Cole still has a job fighting for the innocent children that the childcare system feeds on like potato chips and hoards like precious treasure guarded by dragons.
And Whereabouts Unknown is even more stark and personal than the first book.
Shauna Ellis is fighting with everything that a single mom can do to hold onto her precious son while the system believes they can give a kid living on the edge a better home while his mom shapes up to be a better parent. Nadia knows different... Devon deserves to be a home; and no matter what it costs Nadia will fight the tide that wants to break a solid family apart. Nadia also knows what happens to the kids the system failed to care in the way it claims to.
And those are secrets it wants to keep silent.
For one girl that escaped where the system said it was good... her narrative thread storyline is harrowing, fiery and we the opposite side - a carefully planned underground railroad - holds those that were betrayed and gives them something to hold onto when nothing else exists.
Highly recommended.
Author A.R. Hollowell writes breathtaking dangerous stories that don't sugarcoat the tough conversations these stories invoke.
That's the point. We need these emotional stories.
Nadia Cole still has a job fighting for the innocent children that the childcare system feeds on like potato chips and hoards like precious treasure guarded by dragons.
And Whereabouts Unknown is even more stark and personal than the first book.
Shauna Ellis is fighting with everything that a single mom can do to hold onto her precious son while the system believes they can give a kid living on the edge a better home while his mom shapes up to be a better parent. Nadia knows different... Devon deserves to be a home; and no matter what it costs Nadia will fight the tide that wants to break a solid family apart. Nadia also knows what happens to the kids the system failed to care in the way it claims to.
And those are secrets it wants to keep silent.
For one girl that escaped where the system said it was good... her narrative thread storyline is harrowing, fiery and we the opposite side - a carefully planned underground railroad - holds those that were betrayed and gives them something to hold onto when nothing else exists.
Highly recommended.
Review of advance copy received from Author
A.R. Hollowell has once again written a book that will stay with me long after I have finished! Nadia is a caseworker in the childcare system who takes her job a step farther than most. Because of this she had been terminated but was recently reinstated. She doesn’t just visit and check the boxes. She watches and listens to the parent and the child. Like Nadia, you will become invested in these visits as I did. It shows how things can go horribly wrong and the terrifying thing is I am sure these things really happen.
I really enjoyed this book! I love A.R. Hollowell’s style of writing. Slowly he creates an atmosphere of unease that increases throughout.
Thank you to A.R. Hollowell and Book Sirens for this ARC. I am leaving this review voluntarily.
I really enjoyed this book! I love A.R. Hollowell’s style of writing. Slowly he creates an atmosphere of unease that increases throughout.
Thank you to A.R. Hollowell and Book Sirens for this ARC. I am leaving this review voluntarily.
Review of advance copy received from Author
A slow-burning, emotionally devastating, and thought-provoking thriller that hits hard and stays with you long after the final page.
October 14, 2026
Simply put… wow.
Going into this book, I was expecting another procedural story like Failure To Protect (Book 1 of the series), but this book felt like it had higher stakes, and read like a crime thriller from other authors. The level of care and heart that A.R. Hollowell put into this story is on par with his other work, and the emotional payoff at the end was brilliantly done.
I loved the way he closed the story on background plots from the first book, as well as cashing in the emotional “I know what this can cost” from book one as well.
Absolutely loved this book.
I received an advance review copy for free, and I am leaving this review voluntarily.
Going into this book, I was expecting another procedural story like Failure To Protect (Book 1 of the series), but this book felt like it had higher stakes, and read like a crime thriller from other authors. The level of care and heart that A.R. Hollowell put into this story is on par with his other work, and the emotional payoff at the end was brilliantly done.
I loved the way he closed the story on background plots from the first book, as well as cashing in the emotional “I know what this can cost” from book one as well.
Absolutely loved this book.
I received an advance review copy for free, and I am leaving this review voluntarily.
Review of advance copy received from Author
Nadia Cole is a particularly compelling protagonist. Her personal history and experience as a child-welfare caseworker give her a deeply personal reason to keep digging when everyone else is ready to close the file. The idea of children being reduced to paperwork, statistics, and administrative decisions creates a disturbing backdrop for the story.
Review of advance copy received from Author
This was interesting! Picks up where book 1 left off, but this time more cases are questioned overall. Be ready for lots of twist and turns
Displaying 1 - 7 of 7 reviews