When a dangerous AI weapon disappears, all hell breaks loose in a high-stakes thriller by New York Times bestselling author Jeffery Deaver and Wall Street Journal bestselling author Isabella Maldonado.

A high-stakes theft draws federal agent Carmen Sanchez and brilliant hacker Jake Heron into the hunt to recover the stolen Epsilon Core, a revolutionary autonomous weapon engineered to operate beyond human control.

An enemy in the shadows is assembling the final components to unleash it, causing unimaginable casualties. To stop the unthinkable, Carmen and Jake—experts in exposing intrusion and threats—must track down a mastermind who hides in plain sight behind a perfectly chilling disguise.

Racing against mercenaries, arms dealers, cult conspiracies and a nemesis from Jake’s past, the unlikely partners must navigate a complex and increasingly personal relationship—one put to the test when Jake himself falls under suspicion.

As the clock runs out, and the Epsilon Core’s devastation looms, Carmen must decide if she can trust her partner, a man she may not even recognize anymore.

Jeffery Deaver is the award-winning international and New York Times bestselling author of numerous series, including Lincoln Rhyme, Colter Shaw, and Kathryn Dance, as well as the Sanchez & Heron series with Isabella Maldonado. Deaver’s work includes more than fifty novels, more than one hundred short stories, and a nonfiction law book. His books are sold in 150 countries and translated into twenty-five languages. A former journalist, folk singer, and attorney, he was born outside Chicago and has a bachelor of journalism degree from the University of Missouri and a law degree from Fordham University. He was recently named a Grand Master of Mystery Writers of America, whose ranks include Agatha Christie, Elmore Leonard, and Mickey Spillane. For more information, visit www.jefferydeaver.com.

Isabella Maldonado is the award-winning international and Wall Street Journal bestselling author of the Nina Guerrera, Daniela Vega, and Veranda Cruz series, as well as the Sanchez & Heron series with Jeffery Deaver. Her books are published in twenty-five languages. Maldonado wore a gun and badge in real life before turning to crime writing. A graduate of the FBI National Academy in Quantico and the first Latina to attain the rank of captain in her police department, she retired as the Commander of Special Investigations and Forensics. During her more than two decades on the force, her assignments included hostage negotiator, department spokesperson, and precinct commander. She uses her law enforcement background to bring a realistic edge to her writing. For more information, visit www.isabellamaldonado.com.