In 1783 London, artist Thomas Gainsborough has just unveiled his latest portrait titled "The Anonymous Lady" to great aplomb, as much for the portrait as for the beauty of its unknown subject. In reality, she is a cockney-tongued slum girl known solely as Kitty. Besides Tom, another person who knows her true background is Sir Hugh Marcy, who was in Tom's studio the day Kitty sat for him. One of the many who falls in love with the portrait's subject is the elderly Fitzwilliam, the Duke of Malmunster, who previously let Hugh go from his position at the Foreign Office in favor of the Duke's nephew. With assistance from his ever-inebriated aunt, Lady Susan Dowitt, Hugh carries out a plan: transform Kitty into a lady complete with a back story in order to marry the Duke. The purpose of this plan is twofold: for Kitty to be able to get Hugh his job back at the Foreign Office, and primarily for Hugh to exact revenge on the Duke for letting Hugh go in the first place. Following the transformation, Kitty will be known as Lady Kitty Gordon. Although Kitty agrees to the transformation, she has her own mind and can only take so much training before she breaks. But as the situation around her, Hugh, and Lady Susan changes, Kitty unilaterally changes the plan for a singular purpose. Through it all, she hopes that one person will see what she's doing and do something about it, leading to her own true happiness. But Kitty's fantasy and reality might be two totally different things.
—Huggo