Ok, think of a number between one and ten. Got it? Now keep that in mind as you read the next few paragraphs. John Verdon’s debut thriller plants retired NYPD detective Dave Gurney on an upstate New York farm with his wife Madeleine. An analytical legend and crime-solving superstar in his time, Gurney is having trouble getting in touch with his creative, nature-loving side. Then he settles on a hobby, spending hours indoors putting together digital portraits of serial killers for a local gallery owner. Madeleine is not pleased.

She is also less than thrilled when, inevitably, her husband is pulled back into detective mode. An old friend, Mark Mellery, has been receiving threatening letters that refer to his alcohol-fueled past misdeeds—and they promise retribution. But what really has Mellery scared is a number: 658. It’s the number he came up with when his unwanted correspondent requested that he think of a number between one and a thousand. When it arrives written on the next piece of mail delivered, it means Mellery’s number just might be up.

Parlor tricks do not a good thriller make, however. So Verdon has supplied Gurney with a second puzzle, a interstate serial murder investigation. As Gurney is increasingly drawn back into his familiar surroundings, his marriage suffers. It is this domestic conflict that puts the glue in Think of a Number’s spine, and allows the reader a deeper knowledge of what makes our protagonist tick. We’re connecting more than the dots of a procedural drama here. Verdon knows that the key to a good story is to learn as much about the detective’s demons as the criminal’s. And the number that you had in your head? Now multiply that by zero. Which is how many times you’ll put down this book before finishing.