因持有一名失踪公务员的护照，无家可归的14岁男孩马可在丹麦边境遭到逮捕。警探卡尔·穆尔克及其悬案组负责找出关联的线索。旧案件疑点重重：那名公务员在失踪前不久被指控有恋童癖，结案速度也异常地迅速。然而，沉默受惊的马可不愿开口交谈。他很快就从企图杀人封口的人们手下逃了出来。本片改编自丹麦作家尤西·阿德勒-奥尔森的同名小说，是其“悬案密码”系列的第五部作品。
Andrea had just turned fifteen when he decided to take his life. He seemed to be a happy teenager, with good grades at school and an excellent relationship with his parents. There seemed to be no explanation for what he did, until his mother accessed his Facebook profile and reconstructed the terrifying bullying and cyberbullying her son was going through at school.
