"Dept Q" is a fictional department featured in a series of crime novels by Danish author Jussi Adler-Olsen. This department, dedicated to solving cold cases, is staffed by a small, often unconventional team. Key characters include the cynical and troubled Detective Carl Mørck, his Syrian assistant Hafez el-Assad, and the enigmatic secretary Rose Knudsen. The team navigates complex and disturbing cases, often dealing with themes of social injustice and the lingering impact of past traumas. Their unique dynamic and the intricate mysteries they unravel have made the "Dept Q" series a popular success.