It is 1870, and Mary is forced to scrape a living by keeping a Hampstead lodging house She falls in love with a handsome curate, Richard Cane But sometimes Mary finds herself expressing views which astonish her, and both she and Richard become aware of a 'presence' in the house To her alarm, Mary is swinging forward into the 1970's where she is one of three sisters As the love between Mary and Richard strengthens, their affair has startling repercussions