CHAPTER I—THE TOLL IS EXACTED

CHAPTER II—"FRIENDS OF THE POOR"

CHAPTER III—ENGINEERING-CRIMINOLOGY

CHAPTER IV—THE CAR IN THE FOG

CHAPTER V—THE HAUNTED TREE

CHAPTER VI—THE FLAMING HAND

CHAPTER VII—SPIRIT CLUES

CHAPTER VIII—THE GIRL ON THE HORSE

CHAPTER IX—LUCY

CHAPTER X—CROSSED THEORIES

CHAPTER XI—TELEPHONE CALLS

CHAPTER XII—SATURDAY

CHAPTER XIII—A PUZZLING WARNING

CHAPTER XIV—THE INTRUDERS

CHAPTER XV—THE MASK OF DEATH

CHAPTER XVI—THE FATAL DANCE

CHAPTER XVII—AT THE DOORSTEP

CHAPTER XVIII—TRIANGULATION

CHAPTER XIX—FACE TO FACE

CHAPTER XX—THE INVISIBLE DETECTIVE