Recently graduated Investment-Banker Iris Mayer is found with smashed skull, drugged and dumped afterward on the street, where a graffiti vandal bumps into the corpse. Student boyfriend Tobias Hendrich, conditionally condemned as small dealer and son of attorney Maximilian and now detective Alexander Diring's crucial narcotics informer, says she was stalked by colleague Stefan Groth, who was fired. Reuther also takes an interest in Tobias's too-perfect elder brother's fatal accident years ago.