Denmark, 2013. Police officers Carl Mørck and Hafez el-Assad, sole members of Department Q, which is focused on closing cold cases, investigate the disappearance of politician Merete Lynggaard, vanished when she and her brother were traveling aboard a ferry five years ago.
Denmark, 2016. A blurred note is found in a bottle that has traveled across the ocean for a long time. After deciphering the cryptic note, Department Q follow a sinister trail that leads them to investigate a case that occurred in 2008. At the same time, new tragic events take place that test their faith and deepest beliefs.
Set in the neurosurgical ward of Copenhagen's Rigshospitalet, the city and country's main hospital, nicknamed "Riget", a number of characters, staff and patients alike, encounter bizarre phenomena, both human and supernatural.