A man is found dead in the Omonia underground station and the police investigate the crime. The police officer in charge of the investigation meets and becomes romantically involved with the daughter of the murdered man, even though he suspects that she may know something about her father's activities. However, it soon becomes clear that the deceased had close ties to and collaborated with a large ring of antiquities smugglers. A police agent, who pretends to be interested in buying ancient artifacts, leads to the complete dismantling of the ring and the solving of the crime.