Constance Le Plastrier grew up in the Melbourne suburbs of St Kilda and Hawthorn, a member of a well to do family. She became a teacher and, influenced by the works of Cardinal Newman, was received into the Catholic Church in 1895, a decisive event in her life. In 1900 she moved to Sydney, where she continued her teaching career. She wrote botany textbooks and was the first woman to be elected President of the Field Naturalists' Society. She also edited many Shakespearean plays for use in schools. The author of two novels, she also wrote over a period of 30 years countless short stories for The Messenger, the first appearing in 1908. As 'Erica' she conducted the children's page in the Catholic Press and as 'Mary Lee' she contributed serials to various Catholic papers. However, unless several of her works were published posthumously, she is not the author of a number of stories by Mary Lee which appeared in the late 1940s in the Woman's World Library series (published in London by Amalgamated Press) even though at least one of these, The Strange Story of John Allardyce, does have an Australian setting.