In 2016 Denmark, a mysterious note surfaces from a bottle that has journeyed across the sea for years. The members of Department Q work to decode its ominous message, uncovering a chilling case from 2008. As they delve deeper into the investigation, they encounter fresh tragedies that challenge their convictions and beliefs. This gripping narrative intertwines past and present, forcing the detectives to confront not only the darkness of their case but also the profound implications on their own faith.