seven o'clock in the evening
Further particulars or explanations were denied him , except that he would find a special police officer placed at his service from that moment until he reached his destination , -- which was a polite intimation that he was thenceforth under government surveillance , and that any attempt at flight would be frustrated . He returned at once to his house , which adjoined that of the Marchioness Caldariva . Indeed , from his bedroom a secret passage , already referred to , led into Rozina 's boudoir ; but the clock-door had seldom opened to the secretary of late . Toward seven o'clock in the evening he saw a closed carriage drive away from the next door . `` She is going to the opera , '' said he to himself as he watched the vehicle turn a corner and disappear . He donned hat and coat and sauntered after it , the emissary of the police always ten steps in the rear . Arrived at the opera-house , he purchased tickets for himself and his faithful attendant , and then made his way to the box of the marchioness .