The stories are very similar across the series as well. The plot is most often centered on one inventively masked main villain. The motivations for the crimes are mostly greed, revenge, legacy hunting, and, especially in later movies, things like white slavery and the drug trade. Not unlike the later Italian subgenre of Giallo, the Wallace Krimi movies heavily revolve around the work of the police or a private investigator. Another typical feature is the hapless heroine, and it is not uncommon for the two protagonists to be happily in love at the conclusion of the story. The title sequences of the films were all in color from 1961 onwards, even if the rest of the film was in black and white. Also, in 1962 the voice-over "Hallo, hier spricht Edgar Wallace" ("Hello, this is Edgar Wallace speaking") was added to the beginning of the title sequence in the German versions only. Usually a murder is committed before the film's pre-credit sequence.