She was half delirious with fear and dread; her brain whirled, her heart beat, every moment she dreaded to see Allan Lyster pursuing her.

Her only idea was to get away from him, safe in some refuge where he could not find her.
She little dreamed that in the hurry of her flight she had dropped Allan Lyster's letter--the letter in which he threatened to tell her husband--the letter which drove her mad, and sent her from home.

She had intended to destroy it; she believed she had done so; but the fact was, it had fallen from her hands on the floor, and she never thought of it again.

Her maid, thinking it might be of consequence, picked it up and laid it on the mantelshelf.

Only God knows what would have become of Lady Atherton but for this oversight.
Her absence was not discovered until evening, when it was time to dress for dinner; then the maid could not find her.