Molly Gibson, whose mother has long ago died, is brought up by her father Dr. Gibson. At the age of 17, Molly visits and immediately befriends the Hamleys, her neighbors, especially she and the youngest son Roger Hamley, studying in Cambridge, become good friends. This is when Dr. Gibson tells his daughter of his upcoming marriage to Hyacinth Kirkpatrick, a widower who also has a daughter around Molly's age, Cynthia.
