In northern England around 1900, the worker John O'Brien lives near poverty in a small house in the worker's district. He falls in love with Mary, the teacher of his highly intelligent younger sister Kathy and daughter of a rich family. Their love is doomed by the social difference, but the vigorous Mary refuses to allow outer circumstances destroying their love.

Anne, miserable and rebellious at her parents' recent separation, finds herself drawn to the Watch House, the home of the Garmouth Life Brigade. Something, or someone, is trying to reach her. But what do they want?