Returning home from a wedding, 19-year-old Tilly Trotter is attacked by Hal McGrath, who plans to get his hands on her family's money by forcing her into marriage. Her screams save her, but the incident prompts some villagers to brand her a witch.

While Tilly gets the cold shoulder from the villagers, the McGraths ransack her home, and her grandmother is killed. When Mark Sopwith finds her living in her grandparents' woodshed, he offers her a job as a nursemaid to his four unruly children.

Homeless and out of work, Tilly moves in with Biddy Drew and her children and is welcomed as part of the family. Unable to find other employment, she takes a job at the local mine, where a cave-in leads to a proposition from Mark.

Tilly's arrival at Highfield reawakens old resentments among some of the staff, sparking a mutiny when Mark places Tilly in charge. Tilly grows wary of Mark's feelings for her, while an old enemy returns, seeking revenge.