Guillaume de Saint-Langis

In La Maison du péril, the France Télévisions adaptation of Peril at End House for the TV series Les Petits Meurtres d'Agatha Christie, Guillaume de Saint-Langis is the parallel character of Michael Seton from the original story. Guillaume is seen in a Pathe newsreel taking off on a round the world flight at the beginning of the episode. Like Michael Seton, his aircraft is also named "Albatross". The actor who portrayed Guillaume is not credited.

Guillaume has a different role in this adaptation compared with Michael Seton. Like Michael, he is a famous aviator and a millionaire. However Guillaume is already married. The Pathe news report speculates that he is planning to divorce his current wife for someone else. Guillaume does not go missing during his flight in this episode. The anxiety over his fate is not a factor. Nor is there any will which would later partly provide a motive for murder. What is similar is that Joséphine pretends or leads commissaire Larosière to think that she is Guillaume's secret lover. Larosière would discover later that his lover is not Joséphine but her cousin Eléonore.

Guillaume's plot role in the episode is more to serve as the reason for the presence of Suzanne, who can be thought of as a vague Freddie Rice parallel. Guillaume's wife had so some time suspected that Guillaume was having an affair, and suspected that the other woman might be Joséphine. Madame de Saint-Langis hired Suzanne, who is in reality a private investigator, to keep watch and report on Joséphine.