How much do you think about your grocery lists? Walt, a supermarket janitor with a solitary life, a misanthropic manner and hyper-observant tendencies, thinks about them a whole lot. He's got hundreds of them at home, and he's fixated on piecing together the lives they're part of — especially when they belong to women who live alone. And when those women start going missing in St. John's, Walt's lists may reveal more than the police can uncover.

Wangersky, a newspaper columnist by day, uses his years as a courtroom reporter to tell the story of someone who's "of interest" to the police, even if they don't quite know why.