Spain, late 19th century. Judge Javier Zarco finds in a cemetery a skull pierced by a nail and suspects that a murder has been committed.

British-born David T. Bamberg was a magician who went by the stage name of Fu Manchu. He was so popular in Mexico and South America that he was given the opportunity to star in a series of crime / horror / mystery films between 1943 and 1949. This is one of them.

Madrid, late 19th century. A wealthy woman is found murdered in her home and her maid seems to be the main suspect; but her statement further entangles the case.

Madrid, Spain, early 20th century. A woman turns up dead in a modest home. She turns out to be María la Jerezana, a popular singer who was famous years ago until she disappeared. The Police Commissioner in charge, dissatisfied with the official version, which concludes that the crime was the result of a simple robbery, is determined to find out the truth.

In a dark and stormy night, Raimundo's car suffers a breakdown, so he and Gregorio, his chauffeur, must try to ask for shelter in the only nearby house, a sinister mansion, of those that seem inhabited by ghosts.

This is the Spanish-language version, with a different cast and crew, of the Charlie Chan film Charlie Chan Carries On, in which Charlie sets out to discover the killer of an American found dead in a London hotel room.

Barcelona, early twentieth century. While a trio of masked burglars and their minions search for an ancient Moorish treasure that can only be located when the two parts of an ornamental chain are connected, Inspector Hernández and his faithful assistant Carlos follow the dreadful crime path they walk by. (Only the German cut of the three original Spanish episodes has survived.)

Young couple are trapped in an isolated mansion while members of a criminal gang are killing each other off on the premises.

A murder mystery.

In the Almenares family there is a story involving a mysterious woman and a pearl necklace that obsesses the young heir. He meets Vera, a Polish woman, and invites her and some relations to a hunting weekend, where the necklace disappears.