Something in the story stuck with Lowndes and she quickly wrote out the novel. The basic plot is that an elderly couple take in a border. Soon after, they notice that he has odd habits such as going out late at night, venting a religious mania, and burning certain articles of clothing. Eventually, it is discovered that the man is indeed Jack the Ripper when the family attends an exhibition at the wax museum. The Ripper escapes but is later assumed killed.
Nothing untoward happens to the family but they are very shaken by the experience.
The actual style of the book is somewhat poor. It is not a high literary landmark, to be sure, but Lowndes' style tends to become too conversational and slows the novel's pace. The revelation of the border as the Ripper is, of course, of no surprise to the reader who had been waiting for the old couple to catch on through most of the novel. In fact, the reputation of the novel makes it impossible to obtain much suspense from it. Having been popularized so much by the movie versions, it is unlikely that readers of mystery or horror would not already know the plot.