Originally Aired: July 16, 1957

A Case For Doctor Morelle #13, "Mr X," a mysterious patient with no memory or identification lies recovering in a hospital, while author Paula Maitland finds herself tormented by persistent anonymous telephone calls. The caller's voice, strange and unsettling, repeatedly asks about her overdue second novel, driving the successful writer to distraction and preventing her from working. Inspector Hood refers her to the brilliant Dr. Morelle, who agrees to visit her home that evening to hear the mysterious caller for himself. Miss Frayle, ever eager to help, insists on accompanying the doctor in case danger arises.

However, before Dr. Morelle can investigate, Paula's husband arrives with a shocking allegation: he believes his wife never actually wrote her bestselling first novel, Broken Journey. He claims she returned from a holiday in Devon with the completed manuscript, but her inability to produce a second book reveals her as a fraud. As Dr. Morelle prepares to untangle this web of mystery, the connection between the amnesiac Mr. X and Paula Maitland's literary deception begins to emerge.