Retired homicide detective Dave Gurney hasn't seen Mark Mellery since they were undergraduates, but now Mark, a guru of note, asks for his help. He's received threatening, and mysterious, messages and wants Dave's advice. Dave is slowly drawn into Mark's problems, which become part of a larger, and very dangerous, case, despite the misgivings of Dave's wife, the insightful Madeleine. It's hard to talk about this one without spoilers, but there seem to be some surprising omissions in terms of routine police work that make the plot a bit less credible. But it's certainly suspenseful.