midnight
`` I am true to him , and always have been . But -- he is horribly jealous . I ca n't explain Mr. Dundas ' night visit in a way to satisfy him . If Raoul finds out that an Englishman -- well-known , but of whom I never spoke -- was at my house after midnight , he will believe I have deceived him . Oh , Monsieur , if you would help me to keep this secret I am telling you so frankly ! '' `` Keep the secret , yet use it to free the Englishman ? '' asked the Chief of Police gravely .