Anna Fekete, who fled the Yugoslavian wars as a child, has just started working as a criminal investigator in a northern Finnish coastal town, when she is thrust into a rolling murder investigation. It doesn't help that her new partner, Esko, doesn't bother hiding his racist prejudices.

Anna's work as a criminal investigator barely gets off the ground before she is thrust into a case that has riveted the nation. A young woman has been killed on a running trail, and a pendant depicting an Aztec god has been found in her possession. Another murder soon follows. All signs point to a serial killer. But can Anna catch the Hummingbird before he - or she - strikes again?