How well do you really know yourself?

Abigail Willard first spots her from the back of a New York cab: the spitting image of Abby herself at age 22 - right down to the silver platforms and raspberry coat she wore as a young artist with a taste for wildness. But the real Abby is now 46, married with a corporate job and two kids. As the girl vanishes into a rainy night, Abby is left shaken. Was this merely a hallucinatory side-effect of working-mom stress? A message of sorts, sent to remind her of passions and dreams tossed aside? Or something more dangerous?

As weeks go by, Abby continues to spot her double around her old New York haunts - and soon, despite her better instincts, Abby finds herself tailing her lookalike. She is dogged by a nagging suspicion that there is a deeper mystery to figure out, one rooted far in her past. All the while, Abby’s life starts to slip from her control: her marriage hits major turbulence, her teenage son drifts into a radical movement that portends a dark coming era. When her elusive double presents her with a dangerous proposition, Abby must decide how much she values the life she’s built, and how deeply she knows herself.