The woman who lives there, Gloria, is the most glamorous neighbour on the avenue, owning a fashionable dress shop in Bexhill-on-Sea. But who is the woman who arrives in the black car most Saturdays while Gloria is at work? Sometimes she brings women to the house, and other times the woman also come with children.

Hilda, Katy's mother, disapproves of Gloria. She wonders where these mysterious visitors have come from, and what they want. Does Gloria have sinister reasons for secretly bringing strangers into the heart of the community?

Then one night, the house burns down. In the wreckage, the bodies of Gloria and her daughter are found. Kary is sure the unexplained strangers must be responsible, until her father is arrested and charged with murder. Surely the police have arrested the wrong person? Is the rest of the street safe? Can Katy fin the truth before it's too late?