A CIA analyst hunts an erudite assassin across a high-tech world.
Quinn Mitchell is wounded: by the accidental death of her child, by her estrangement from her husband, by her deflated self-confidence and loneliness. But even wounded as she is, she is CIA Deputy Director Townes' best analyst, and when an analyst is needed to assist Interpol in catching the Elite Assassin, she is the choice. This establishes one plotline, but there's much more going on. The assassin Ranveer, a gentleman of impeccable taste and manners, globe-hops from job to job on Emirates Airlines, kills in a variety of high- and low-tech ways, and leaves each victim marked with a four-digit identifying number. He is revered and respected by all. Quinn's job is to try to find a pattern, or patterns, in his methods, travel, numbering, anything that might shape an AI analysis—and she has some success. Sent into the field, she gets close to him but is always a tantalizing step or two behind. Meanwhile, researchers, in particular physicist Henrietta Yi, a CIA contract employee, are attempting to decipher a coded message discovered in the Large Hadron Collider that appears to have come from the future. When Quinn traps Ranveer, the assassin reveals that he has deciphered the message and that in fact it's a set of instructions to assassinate specific individuals, sent from the future, apparently to avert or suppress misery and chaos then. The CIA is aware of this, and Ranveer, though not an employee, is acting in their interests. But it turns out there are crosscurrents in the future, too, and Dr. Yi may have something to say about the CIA's tendency to aid and abet established interests. All this takes place in an only slightly futuristic world that snaps and bristles with technological capabilities that may seem distant or improbable but which are in fact just around the corner. (Cantrell is a software engineer as well as a writer, and he knows the territory). There's snappy dialogue, sharp observation, and compelling characters in Quinn, Ranveer, and Henrietta; the technology sings, the physics is plausibly presented, and the suggestion of time travel fascinates.
A fast, fun, and intelligent SF thriller.