Translations for realm in French

Here are paragraphs from public domain books translated:

“There is a realm in which the most acute and most experienced of detectives is helpless.”	— Dans certain domaine, le détective le plus expérimenté et le plus subtil demeure impuissant.
The Hound of the Baskervilles, by Arthur Conan Doyle	Le Chien des Baskerville, de Arthur Conan Doyle