Senior citizen Elke Schmidt receives a mysterious phone call in which an unknown person pretends to be her son. Only a few hours later she is dead. When the detectives arrive at the scene of the crime, the mood is depressed. Who killed the defenseless senior citizen? The food delivery man Halil Fahimi has found them and quickly moves into the circle of suspects. There is unrest among the residents. Neighbor Frank Wollny thinks he has long since seen through the situation. But the motive remains unclear at first. Initial investigation results do not point to a robbery-murder, but to a so-called grandchild trick. The victim had been asked for money by phone shortly before. It seems as if the scam has come to a violent end.