In disgrace with her aristocratic in-laws, recently widowed Lady Fieldhurst is exiled to Scotland with her three young nephews in tow. On impulse, she and the boys decide to stay at an isolated seaside inn under an assumed name, where they can enjoy a holiday far away from the scandal that still plagues the family.

But trouble soon finds them when the boys discover an unconscious woman on the beach--a woman who bears a startling resemblance to the local laird's daughter, missing and presumed dead for the last fifteen years. Uncertain whether to welcome her as a returning prodigal or denounce her as a fraud, Angus Kirkbride sends to London for a Bow Street runner--which presents a dilemma for Lady Fieldhurst, since she has chosen to call herself Mrs. Pickett after the handsome young man who saved her from hanging for the murder of her husband.

Meanwhile John Pickett, hopelessly pining for Lady Fieldhurst, resolves to forget her by marrying another. When magistrate Patrick Colquhoun receives Kirkbride's summons, he packs Pickett off to Scotland before his most junior runner can do anything rash.

Upon his arrival, Pickett is surprised (though not at all displeased) to discover that he has acquired a "wife" in the person of Lady Fieldhurst. But when Angus Kirkbride dies only hours after announcing his intention of changing his will in his daughter's favor, "Mr. and Mrs. Pickett" must join forces to discover the truth about a family reunion suddenly turned deadly.