midnight
` Um . Was the door fast on your return ? '' `` No , it was pulled to , but it was open all the same . '' `` You did n't happen to lose your latch-key during your midnight stroll , sir ? '' `` No , it was only when I put my key in the door that I discovered it to be open . I have a spare latch-key which I keep for emergencies , but when I went to look for it just now the key was not to be found . When I came back the house was perfectly quiet . ''