Kirsty, an 'orphan brat' escapes from the remote Ayrshire farm where she was a servant and runs away with her sweetheart, Craig Nelson. With little money and still strangers to each other, they travel to Glasgow and set up in a 'marriage' that is never made legal. 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 . . .