Civil engineer Berger is looking for his mother and learns that she has died and was last in a home run by the notorious construction company Huberty. When the company boss Huberty becomes the victim of an assassination attempt shortly afterwards, suspicion falls on Berger, but Huberty's death is linked to the fraudulent bankruptcy of the construction company. The boss's wife is found to be the culprit. An unpleasant surprise awaits Berger, a civil engineer from Hamburg, when he returns home after years of working in Mexico: his mother has disappeared. Her tracks are lost in a "retirement home" run by the Huberty Society. Berger suspects that his mother has been the victim of a crime. He hunts a murderer and becomes the hunted himself...