A strange murder is done in the parking hall at the airport. When the police come, the three men who found the victim are gone. They are automatically suspected, but nothing is as it first seems.
The owner of a "sauna club" is found murdered in his car. An employee's teenage son has a history of condemning the club and especially his mother's involvement, but Derrick knows the case is seldom that simple.
Ursula is released from juvenile criminal custody. A strange man picks her up by the road and drives her to the city. That very night she witnesses his murder.
In spite of Derrick's advice, young Mr. Hässler conducts his own investigation to find his grandmother's murderer. The only lead he has is a blue rose tattooed on the man's wrist.
A young prostitute is found strangled in a park. The only lead left by the perpetrator is a hat lying on the ground. The scent hound leads the cops to a house where all the tenants appear a bit strange.
Ali, a small time pocket picker and purse snatcher, is proposed a better paying career in breaking and entering. On his first gig he becomes involved in a sinister plan.
