Twins

Ivy and Isla Mercer were born identical in every way that the world could measure. What the world could not measure - what their father suspected and their mother refused to see - was the specific quality of their interior life: cold, precise, collaborative, and entirely without the ordinary human friction that prevents most people from acting on their worst impulses.

They were eleven when they first tested what they could do. They were fifteen when they first killed. By the time they graduated and moved to Chicago as independent adults, they had refined their method into something close to art - clean scenes, no evidence, and a signature number, twenty-three, embedded in every target selection.

Twins follows Ivy and Isla through four distinct phases of their lives, each one extending the reach and the sophistication of what they do. Part One establishes their childhood in a small Midwestern town, where their father's protection and their mother's growing dread create the specific atmosphere in which two people can become something that has no name. Part Two moves them to Chicago, where Detective Mara Langley - who has been watching them since the first body - builds her case through obsession and instinct while the twins build their philosophy. Part Three turns on the single question the novel has been moving toward: what happens when one of the two begins to want something the other does not? Part Four relocates to Paris, where the twins reinvent themselves with new names and a new geography and find that Mara Langley has followed them across the ocean.

Twins is a novel about the specific horror of a mind without doubt - and the more specific horror of watching that certainty begin, for the first time, to develop a crack.