The wrong answer can cost everything.

When brilliant math professor Ivy Reeves receives a cryptic note bearing her name at a crime scene, she’s drawn into a deadly game where probability becomes a matter of life and death.

Thirteen victims. Complex mathematical puzzles. A killer who understands that some games are designed to be lost.

As Detective Vaughn Ryan races against the clock, he needs Ivy’s genius to decode the twisted logic behind each murder. But the closer they get to the truth, the more personal the game becomes. The killer knows Ivy’s past—the fire that destroyed her family, the secrets she’s buried, the father she visits wearing a mask over his melted skin.

Every number has meaning. Every equation points to the next victim. And time is running out.

From New York Times bestselling author J.D. Barker and Patrick Logan comes a pulse-pounding thriller where mathematics meets murder, and one wrong answer means death.

Praise for J.D. Barker

“J.D. Barker is a one-of-a-kind writer and that’s a rare and special thing. Stephen King comes to mind and Lee Child, John Sandford. All one-of-a-kinds. Don’t miss anything J.D. writes.”
—James Patterson, #1 International Bestselling Author

“A talented writer with a delightfully devious mind!”
—Jeffery Deaver, NY Times Bestselling Author

“I don’t say this lightly: J.D. Barker is a force to be reckoned with.”
—Tosca Lee, NY Times Bestselling Author

“JD Barker is an author to watch in the coming years.”
—Rolling Stone

“What sets Barker apart is his unique ability to blend genres seamlessly. His novels are a masterful fusion of horror, crime, mystery, science fiction, and the supernatural, creating a reading experience that is both thrilling and thought-provoking.”
—CULTR.com

“J. D. Barker is quickly becoming one of the best thriller writers working today.”
—Book Reporter.com

“Devilishly dark.”
— Library Journal

“Barker is a master wordsmith.”
— AudioBookReviewer.com

“Masterful storytelling.”
— Bookish

“J.D. Barker knows how to set a scene.”
— Pittsburgh Post-Gazette

“...on par with Stephen King, Joe Hill and especially, Dan Simmons. Riveting and relentless.”
— BookTrib

"J.D. Barker was born to write suspense thrillers."
—The Real Book Spy

“It is clear Barker is a name to watch.”
—The Horror Bookshelf

“Barker’s slight of literary hand is absolute genius. He builds tension and then rips the rug right out from under you, just to do it all over again.”
—Quitterstrip

“Mr. Barker may have begun by following in the footsteps of such literary royalty as Stephen King, Thomas Harris, and Dean Koontz, but he has blazed a unique path all his own.”
— Fresh Fiction

“J.D. Barker is quite frankly one of the best crime thriller writers out there who should be on everyone’s radar!”
— Novel Delights

“Barker is an award-winning writer who is the second coming of Thomas Harris.”
— Book Reporter.com

“Barker's mastery of character and dialogue is noteworthy.”
— Booklist

“Barker is the Mozart of thrillers!”
— GoodReads

“Barker is such a skilled and exciting writer, delivering a chilling, slow-build thriller, a final, jaw-dropping twist, and a cliffhanger ending that leaves readers dangling precariously by their fingertips.”
— Lancashire Evening Post

“Mr. Barker doesn't just tell a story, he paints pictures with his words.”
— BookBub

“If you haven't read any J.D. Barker, I strongly suggest you start now.”
— Goodreads