After completing a dangerous mission training police officers in war-torn Afghanistan, Detective Maria Kallio returns to Finland as the head of a new special crimes unit. But what awaits her in her home country is her most challenging and unsettling case yet. Three immigrant Muslim girls, all members of the same social club, have gone missing under mysterious circumstances. When the body of a fourth girl is found in the snow, strangled with her own headscarf, the investigation takes on a grim new urgency. Is there a xenophobic serial killer on the loose? A random white nationalist? Or does something more insidious bind the girls? In a Finnish city struggling to assimilate a new population of Muslim immigrants, the answers are hard to come by ... One thing is certain: it will take a detective familiar with the darkest depths of humanity to sift through the wreckage of clashing cultures in search of the truth. That detective is Maria Kallio.