In the novel Hallowe'en Party, Mrs Minden is one of the adults who were present at the preparation session for the halloween party during which Joyce Reynolds announced that she had once seen a murder in the village. She is a cleaning woman who works at various households in the village Woodleigh Common. Her name is on the list of people present at the preparation session which Superintendent Spence compiled for Poirot. Poirot was working on the premise that one of those present must have heard Joyce and been alarmed by what she said and so killed her.
Among the households which Mrs Minden worked for was that of the late Mrs Llewellyn-Smythe. While there, she heard her employer tell her au pair Olga Seminoff to write a letter for her. She was to make the handwriting as similar as possible to hers and then she would sign it. Mrs Llewellyn-Smythe disliked typed personal letters. From this, Mrs Minden concluded that Olga was used to copying her mistress's handwriting. Mrs Minden contributed this to the general village gossip and this became grist to the mill when it emerged that a codicil to Mrs Llewellyn-Smythe's will had been forged.
During the time of the novel, Mrs Minden cleans at the house of Judith Butler among other places. Miranda Butler had missed the halloween party because she was sick. Mrs Minden later told the news of Joyce's death to Mrs Perring, who then told Miranda that her friend Joyce had been murdered.