When the parish guardians send Lydia, daughter of convict James Knowles, to apprentice in the cotton mill at Caton, she is distraught at being parted from her younger siblings and mother, Betty, but she has no choice. At the mill, Lydia is bullied by some of the other girls and things do not go well when she stands up to the ringleader. Fearing she has killed someone and with the word murderess ringing in her ears, Lydia runs for her life. Meanwhile, Betty and her children have been granted passage to Australia to join her husband, but Lydia cannot be found so Betty is forced to leave without her. When Lydia arrives home to find her family has gone she is determined to follow them, all the while avoiding the law who seek to return her to the mill.