After Adam Barnett of Defiance, Arizona, is struck by lightning, he awakens with a gap in his memory and an unfamiliar dog licking his face, whom he calls Mop. Shortly afterward, he’s attacked by “something out of a nightmare” that he’s unable to identify. He manages a narrow escape with Mop, who turns out to be a runaway government research animal linked to a dangerous web of secrets. Simultaneously, Maj. Blain Jacobson, a U.S. Army Ranger with extensive combat experience and high-level analytical skills, uncovers more than he bargains for when he looks into a fatal incident at a government research facility in North Scottsdale, Arizona. Elsewhere in the state, Victoria Stewart, the daughter of a deceased U.S. Marine veteran and the survivor of an attempted car bombing, desperately searches for a man she knows only as “Dark,” whose voice haunts her in her dreams, as he orders the killings of real people who later turn up dead. These three strangers’ fates intertwine as they try to root out the truth of their tangled predicaments—but, in each case, one misstep could prove fatal. Ewing excels at immersive, pulse-pounding action scenes with visceral detail. The clipped, no-nonsense language works alongside meticulous attention to specifics: “He was in the northwest corner. If he headed toward the south lobby, he might run into whomever or whatever had shut off the lights. The loading dock was behind the killers to the north, so that was out.” As the characters sustain significant injuries that affect their ability to function at top capacity, the stakes become clearer. The book occasionally has trouble juggling its three complex, integrated plotlines, and it sometimes meanders; some characters’ interactions feel awkward at times as well. But the various players’ motives are sympathetic enough to sustain the plot, and a satisfying conclusion leaves room for the story to continue.