It's the 1820s. Since losing their parents, Kate and Andrew have been living with their cold-hearted aunt and uncle within the vaults of Edinburgh's South Bridge. Worked relentlessly by day and tormented at night, Kate has little chance to secure a different way of life for herself and her younger brother. Then one day Richard Hope walks into her life. A wealthy medical student, Richard knows that despite their different backgrounds she is the girl for him. Instantly smitten, Richard vows to do whatever it takes to spend his time with her. But as the romance develops, not everyone is happy for the young lovers ... Can their fragile relationship survive the pressures of family betrayal and society's disapproval, or will they be forced to part?