Esther Nentwig, the illegitimate child of Gabriel Fischer-Hellwarth, a very wealthy and powerful businessman and banker, is invited to his birthday party out of the blue, without knowing that almost the entire family will not give her a very warm welcome. While Gabriel is trying to introduce Esther to her siblings in front of the family, Esther discovers Adrian, son of Marion Fischer Hellwarth, Gabriel's youngest daughter, lying unconscious in the swimming pool in front of the villa. She saves his life, which at least gets her sympathy from Marion. At the same time, Barbara Fischer-Hellwarth, daughter of Peter, Gabriel's eldest son, disappears without a trace and is found murdered a short time later. Inspector Keller, an old friend of the Fischer-Hellwarths, takes over the investigation.