The Sign at Six

I The Owner of New York II The Shadow of Mystery III The Moving Finger Writes IV Darkness and Panic V A Scientist in Pink Silk VI The Wrath to Come VII A World of Ghosts VIII Percy Darrow's Theory IX The Great Silence X The Lifting of the Spell XI Thirty Seconds More XII The Unknown XIII Darrow's Challenge XIV The Fear of Danger XV The Master Speaks Again XVI The Professor's Experiment XVII Drawing the Net XVIII Confusion Worse Confounded XIX Percy Keeps Vigil XX The Plague of Cold XXI In the Face of Eternity XXII The Man Next Door XXIII How It All Was XXIV What Happened Afterward