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.

When a body is found on the bridge between Denmark and Sweden, right on the border, Danish inspector Martin Rohde and Swedish Saga Norén have to share jurisdiction and work together to find the killer.