19th century. Kirsty Barnes, an orphan indentured to a lecherous old farmer, escapes from his advances with the help of her childhood sweetheart, Craig Nelson. With little money and still strangers to each other, they travel to Glasgow. Marriage takes second place to survival, although their fortunes improve when a churchgoing widow befriends Kirsty. Still not legally married, Kirsty gives birth to a son, and Craig establishes his reputation as a policeman. Ambitious and impatient to get on, Craig falls in with a gang of sly and vicious thieves and soon sinks into a life of drink and crime. Meanwhile, Kirsty has met the handsome and charming David Lockhart, a medical missionary soon to return to China. But she is bound by loyalty to Craig, a less than ideal husband who can only bring her hardship and heartbreak...