| I | A Double Tragedy |
| II | The Investigation Opens |
| III | At the Greene Mansion |
| IV | The Missing Revolver |
| V | Homicidal Possibilities |
| VI | An Accusation |
| VII | Vance Argues the Case |
| VIII | The Second Tragedy |
| IX | The Three Bullets |
| X | The Closing of a Door |
| XI | A Painful Interview |
| XII | A Motor Ride |
| XIII | The Third Tragedy |
| XIV | Footprints on the Carpet |
| XV | The Murderer in the House |
| XVI | The Lost Poisons |
| XVII | The Two Wills |
| XVIII | In the Locked Library |
| XIX | Sherry and Paralysis |
| XX | The Fourth Tragedy |
| XXI | A Depleted Household |
| XXII | The Shadowy Figure |
| XXIII | The Missing Fact |
| XXIV | A Mysterious Trip |
| XXV | The Capture |
| XXVI | The Astounding Truth |