Nine-year-old Emily Anne Toussaint is shot dead on a Montreal street. A North Carolina teenager disappears from her home and parts of what may be her skeleton are found hundreds of miles away. For Dr. Temperance Brennan, a forensic anthropologist in both Montreal and North Carolina, the deaths kindle deep emotions that propel her on a harrowing journey into the world of outlaw motorcycle gangs. As a scientist, Tempe should remain dispassionate. As a caring individual, she yearns to take the killers off the streets. Emily Anne was cut down in a biker crossfire. The North Carolina victim, Savannah Osprey, was last seen hitching a ride with a transient biker. Tempe's nephew, Kit, is intrigued by motorcycles. Does he understand the difference between legitimate riders and gangs, or is he too mesmerized to comprehend that outlaw bikers are big trouble? With her boss Pierre LaManche in the hospital, and her friend Andrew Ryan disturbingly unavailable, Tempe begins a perilous investigation into a culture where evil often wears a mask.