four o'clock
`` This is a serious case and you will be wanted as a witness , '' said the officer . `` You did n't know these people -- never saw them before ? '' `` No . I had come to the park to kill time until four o'clock , when I have an engagement at the Plaza Hotel . '' The officer noted carefully his description of the woman who had assisted in the kidnaping and such meager facts as he was able to give as to the man who had carried off the little girl under the very eyes of her mother . The sergeant glanced at Archie 's ruddy handkerchief and grinned . `` Guess that let 's you out !