On her way home after a celebration in her small, rural hometown, a young woman – Karla Petersen – is murdered. Helen Dorn, whose father is still in a coma, takes on the case.

In the countryside, she meets local officer Tom Petersen, Karla’s brother. In spite of Dorn’s warnings not to get mixed up in the case, he relentlessly searches for his sister’s killer, suspecting friends and acquaintances alike.

Surveillance on an illegal arms trafficking case has spun out of control. Three Polish men are dead, two of them policemen. Mattheisen discloses his conspiracy theory to Helen Dorn: he is convinced that the weapons delivery was intended for an underground right-wing radical group, infiltrated by a mole from the State Office of Criminal Investigations. But before Mattheisen has a chance to tell Helen who is behind it, he is shot and killed with Helen’s service weapon. And Helen is found at the scene of the crime by her colleagues, gun in hand and no memory of what happened.