Rio de Janeiro, 1913. The Secretary of the Presidency of the Republic is murdered at the former home of the Marquesa de Santos, known as the House of Exchanges, a sophisticated brothel where secret meetings take place. Under the guise of a medical clinic, the brothel is run by a scientist obsessed with the study of female sexual fantasies. During the criminal investigation, a forensic expert who frequents the House comes face to face with a rogue from Cais do Porto possibly involved in the murder. The two begin a competition to figure out who is the greatest seducer.