midnight
The photograph was of Irene Adler herself in evening dress , the letter was superscribed to `` Sherlock Holmes , Esq. . To be left till called for . '' My friend tore it open , and we all three read it together . It was dated at midnight of the preceding night and ran in this way : `` MY DEAR MR. SHERLOCK HOLMES , -- You really did it very well . You took me in completely . Until after the alarm of fire , I had not a suspicion . But then , when I found how I had betrayed myself , I began to think .