"A twisty, mind-bending thriller that will keep you guessing until the final gut punch." --Leigh Bardugo

"Past lives and parallel lives, crime and potential punishment--but the most thrilling thread here is facing belief in a wild theory, a worldview changing, as the theory becomes the most sensible one on the table. Heisserer has outdone himself." --Josh Malerman, New York Times bestselling author of Bird Box

From the Oscar-nominated screenwriter of Arrival comes a phenomenal speculative thriller about a federal agent and a therapist who team up to stop an otherworldly killer.

Federal agent Grant Lukather works for an unknown department of Homeland Security called Predictive Analytics. They look for patterns in tips and chatter to prevent a terrorist event before it happens. One of these calls, about a possible explosion in New Mexico, leads Grant to a case with unimaginable consequences.

He meets Sarah Newcomb, a therapist who uses past-life hypnosis in her treatment but has recently stumbled upon a phenomenon that seems to defy logic. Grant follows this thread to another crime: a copycat killer case in Colorado. With the help of one of Sarah's patients, they embark upon an investigation that spans multiple states, timelines, and consciousnesses. With limited time and only a tenuous grasp of how this phenomenon works, the unlikely trio are in a race for their lives--past, present, and future.

Full of thrilling reveals, stunning plot twists, and a mordant sense of humor, Simultaneous is a mind-bending, one-of-a-kind thriller by a true genre star.