midnight
I brought him here under an assumed name , and he remains shut up in his rooms all day , and only ventures out at night to breathe the fresh air . His mind has never recovered its tone since that brain fever . He has become a monomaniac on one subject , the dread of being discovered , and hanged for murder . Nothing will tempt him from his solitude -- nothing can induce him to venture out , except at midnight , when all are asleep . He is the ghost who frightened Margery and Agnes Darling ; he is the man you saw with Kate last in the grounds . He clings to her as he clings to no one else . The only comfort left him in this lower world are these nightly walks with her .