A turbulent night in Mainz: Alcohol and riots determine the police operations. In front of a nightclub, the old town guard has to mediate between bouncers and a very drunk guest. And the KDD is called to a body found at a bus stop.

Nighttime search operation for the Mainz Old Town Guard: Will they find the boy in time who announced his suicide after an argument? Meanwhile, the criminal investigation service makes a grisly discovery: a badly decomposed corpse in a house completely littered with rubbish.

An alarming radio message reaches the Old Town Guard team. Shots are said to have been fired in a Mainz residential area in the middle of the night. To protect themselves, the officers have a dog with them, which could more easily overpower an armed perpetrator.

The highway police have to secure an accident scene in the middle of the night. A deer lies run over on the road. The situation is risky, also because a car is racing towards the officers without braking. The old town guard is also called to a dangerous mission: a robbery with several people injured.

The KDD is called to a break-in in downtown Mainz. The victim is missing a weapon. He knows the alleged perpetrator and suspects that he is planning further attacks. Meanwhile, in the city center, a motorcycle gang is making the streets unsafe, and the Old Town Guard is in pursuit.

A restless night for the KDD: First the investigative team is called to an armed robbery at a gas station, then a break-in at a scrapyard is reported. They find a suspicious car near the crime scene and discover several bolt cutters in the trunk.