It's early summer in Stockholm. Agneta and Stellan Broman have just waved off their daughters and grandchildren when the landline phone rings. The caller says just one word: "Geiger." Agneta hangs up, finds her old pistol, kills her husband of fifty years and then disappears from their home without a trace. Sara Nowak, a police officer in the prostitution unit, is called by a colleague who is investigating the murder. Against regulations, Sara gets involved in the investigation. It is the beginning of a dark journey, leading back to the Cold War and fatal ideologies, and the truth about Sara's own childhood.