The suitcase she found changed everything. The contents? An elegant dress and an invitation in another girl’s name. Twenty-three-year-old Mary would go to the ball, enjoy how the rich lived just for one night, and then quietly slip back into her real life, sorting rubbish as a poor barmaid. No harm done. Of course, there wouldn’t be much of a story to tell had it turned out that way.

It’s 1870 in rural England, and Mary assumes the identity of the suitcase owner, Agnes. When Mary’s one night at Mannerley estate turns into a seven-day, hilarious farce, she quickly makes friends, finds suitors, and keeps fibbing. Not only does Arthur, the heir himself, fall for her, but so, too, does Mr. Singh, his friend visiting from India, making advances in plain sight of the heir. Making matters worse, a former workmate recognizes Mary and extorts her: she must steal a golden watch from the heir for him or have her true identity exposed and risk being thrown in jail, which could mean death––and that would certainly ruin her stolen, er, borrowed ball gown.

The only way Mary can get close enough to Arthur to steal his watch is via sensuality and flirtation. But as Mary scrambles to cover her tracks, her lies and crimes compound, weaving themselves into an impossible tangle. All the while Agnes, the real owner of the fancy ball gown, is making her way ever-closer to Mannerley. Happily ever after seems as unlikely as a barmaid among dandies, when Mary's only possible escape is a confession and the hope her scandalous true love will risk his reputation to defend and forgive her.