In the novel Nemesis, Janet is a woman daily help at The Old Manor House in the village of Jocelyn St. Mary. As a young girl, she had worked at the house as a housemaid. At that time the owner was Colonel Bradbury-Scott who managed a fair sized household with a cook, parlourmaid, housemaid, kitchenmaid and even kept horses and a groom. After the Colonel died, he left the house to his only remaining relations, the three sisters Clotilde Bradbury-Scott, Lavinia and Anthea. By the time of the events in the novel, Janet was quite elderly and, given the reduced circumstances of the three sisters, she was employed part-time and came in only in the mornings.
Janet was the first to give Miss Marple important background information about the various old crimes committed in the village, including the murder of Verity Hunt. Verity had been involved with someone named "Michael". This gave Miss Marple an idea about what injustice it was that Mr Rafiel wanted her to look into.
Janet is not featured in BBC's 1987 adaptation of Nemesis. There the three sisters employed a stay in cook named Mrs Adams.