This is a story of Clarence and Emmeline Mumford are a middle-class couple, living in a rural area near to London with their two-year-old son. They advertise for a "paying guest", or lodger, to supplement their income. A young woman named Louise Derrick answers the advertisement, in need of a place to live due to disagreements with her immediate family. Louise, who is poorly educated and bad-tempered, is being romantically pursued by two men: Mr Bowling, who is courting Louise's stepsister Cecily, and Tom Cobb. The Mumfords do not get on well with their "paying guest", and attempt to persuade her to leave. This does not happen, and a series of events further disrupts the Mumfords' lives, including a private meeting between Louise and Clarence Mumford, which makes Clarence's wife jealous. Louise encourages Bowling's wooing of her, believing that his courtship of Cecily is over, but Cobb makes a surprise trip to the Mumfords' home to pursue Louise. Cobb accidentally starts a fire in the drawing room of the property, severely injuring Louise, who is then confined to bed for several weeks.