one o'clock
`` You are very good , madame , but it is necessary that I go ! When can I see the _ concierge _ ? '' `` The _ concierge _ , monsieur , is my husband . He will be here for a certainty at one o'clock . '' `` Good , madame ! At one o'clock I shall return . '' He smiled , nodded , and ran down the first flight of stairs ; but by the window at the half-landing he stopped and looked back .