ten o'clock
`` They seem to be everywhere to-night , '' John laughed carelessly . The White House door was open and they passed into the hall and ascended the stairs to the Executive Chamber without challenge . Little Tad , the President 's son , who ran the House to suit himself at times , was in his full dress suit of a lieutenant of the army and had ordered the guard to attend a minstrel show he was giving in the attic . The President had agreed to meet Betty in his office at ten o'clock and told her to bring her friend right upstairs and wait if he were not on time . They sat down and waited five minutes in awkward silence . Betty was watching the strange glittering expression in John Vaughan 's eyes with increasing alarm . She heard a muffled footfall in the hall , stepped quickly to the door , and saw the man they had passed at the entrance to the grounds .