Ivan Canabrava is a writer, turned insurance ivestigator who investigates mysterious deaths involving Bufo Marinus. Bufo Marinus is a frog poison causing catalepsy in humans, simulating death, enabling grand insurance fraud and other crimes. Ten years later, now as a successful writer, similar characters possibly using Bufo Marinus reappear and create an intricate plot full of surprises.
Rio de Janeiro, 1886. A precious Stradivarius violin presented to Emperor Dom Pedro II is stolen. Sherlock Holmes and Dr. Watson are called to solve the case.
This film shows three episodes: "The First Sin" portrays the relationship of a man and married woman; in "Devilish", the desire between a young woman and her brother-in-law is shown; and in the episode "Cachorro!", a man sees his wife with her lover.