Anthropologist and prehistorian Prof. Dr. Crusius, accompanied by his assistant Karl Mill, is tracing the footsteps of early humans. He aims to prove the existence of a human being from a hundred thousand years ago. Furthermore, he is convinced that an animal soul resides within every human being. He faces hostility because of his theory and receives anonymous threatening letters. He delivers a major lecture before the anthropological society. Ultimately, the professor is even forced to fight a duel with an adversary over his hypothesis.
| Actor | Role |
|---|---|
| WWalter SchmidthässlerProf. Dr. Crusius, Naturforscher | Prof. Dr. Crusius, Naturforscher |
 Rita ClermontEva, seine Tochter | Eva, seine Tochter |
| JJenny MarbaTante Mary, seine Schwester | Tante Mary, seine Schwester |
 Heinz SarnowDr. Ludwig Haller | Dr. Ludwig Haller |
 Eugen RexProf. Dr. Fellner | Prof. Dr. Fellner |
| RReginald PaschKarl Mill, Assistent des Prof. Crusius | Karl Mill, Assistent des Prof. Crusius |
| HHannah HouglandEdith, Mädchen bei Crusius | Edith, Mädchen bei Crusius |
| LLudwig RexNot listed | Not listed |