The available position is in the employ of Adams' Delysia Lafosse, who is looking for a 'social secretary" because she has heard that all successful movie stars have one. Since she hasn't a clue what a social secretary might actually do, she's not bothered that Miss Pettigrew lacks any credentials for being one. At the moment of Miss Pettigrew's arrival at Delysia's swank penthouse apartment, Delysia is in a swivet because she must get rid of a rich and well-connected playboy, aptly named Phil Goldman (Tom Payne), who is lying blissfully naked in her bed. Phil must go before a rich but pugnacious playboy, aptly named Nick Colderelli (Mark Strong), arrives for a morning tryst. Delysia would like to resist Nick's expected advances, but he has given her a singing job at his nightclub, and he is paying the rent on her apartment. Moreover, as Delysia understands about herself, she's a pretty pitiful resister.
Consequently, Miss Pettigrew's essential first assignment is to expedite Phil's departure, an added challenge because she has so little experience with naked men. And no sooner has she gotten Phil into the elevator than she has to blunt Nick's suspicions about the cigar stub he finds in an ashtray. Delysia is not without her talents, but housekeeping and punctuality are not among them. Lies are told, oaths are uttered, distasteful acts are committed and deft, sharply choreographed comedy ensues.
Meanwhile, the wolf is at the door. The setting is London, 1939, and in the background we see newspaper headlines about failing negotiations between England and Hitler's Germany. In the foreground, we have the soup lines from which Miss Pettigrew emerges. The world is a scary place, and that fact is central to Delysia's calculated career maneuvers. Though she is young and Miss Pettigrew is middle-aged, the former gorgeous and the latter plain, the two actually have critical things in common. Both come from modest circumstances, and both are on their own. Miss Pettigrew has resigned herself to an ordinary life, but she surprises herself with her adaptability. Delysia dreams of stardom, and she uses her sexuality as a tool to get what she wants. But the picture forgives her this from the outset because like Miss Pettigrew, her survival is at stake.
On the whole, the film might have more staying power if it explored, even in its comic vein, these issues of expediency more extensively. But in the end, the picture is a combination of the ugly duckling story and a come-to-your-senses romantic morality tale. Under Delysia's tutelage, Miss Pettigrew blossoms and attracts the attentions of wealthy clothier Joe Blumfield (Ciaran Hinds). And yielding to Miss Pettigrew's superior wisdom, Delysia lets penniless and powerless piano player Michael Pardue (Lee Pace) back onto her crowded romantic playing field. In short, the picture chooses to be safe rather than edgy. But that doesn't mean it fails to please; it is charming in each of its brisk 95 minutes.