Upon seeing "Miss Pettigrew Lives for a Day," two words chime in one's head: nice, and slight. A period-set comedy taking place in London on the eve of World War II, the film feels like it could have actually been made in the 1940s. The story—a rags-to-riches-to-rags-to-possibly-riches tale taking place over an eventful twenty-four-hour timeframe—is as dusty as a trunk that's been left in the attic for sixty years, and it's every bit as predictable as, say, the recent "The Hottie and the Nottie." Narratively speaking, the picture, directed by Bharat Nalluri (2000's "The Crow: Salvation"), is shopworn and nothing special, its only spark of freshness being the background shading of a bustling city about to be deeply affected by the approaching war. What is a step above, however, are the deliciously engaging performances from Frances McDormand (2005's "North Country") and Amy Adams (2007's "Enchanted"). They almost make "Miss Pettigrew Lives for a Day" worth a look.

Having unfairly lost her job as a nanny, Miss Pettigrew (Frances McDormand) is penniless and in dire need of a job. When her employment agency is of no help, she takes a chance and shows up at the door of Delysia Lafosse (Amy Adams), a harried, somewhat flighty lounge singer and wannabe actress currently juggling three men. Phil (Tom Payne) promises her a part in an upcoming hot-ticket West End play in exchange for her "attention." Nick (Mark Strong), whose luxurious apartment Delysia is staying at, is a club owner promising her great wealth. And Michael (Lee Pace) is her trusty partner in her lounge act, low on money but the only one who sees the lovely person she is on the inside. Having helped her out of a tight, potentially disastrous, spot involving Phil and Nick, Miss Pettigrew is promptly taken under Delysia's wing. Posing as her new "social secretary," this down-on-her-luck governess is about to experience an unforgettable whirlwind day of fashion shows, makeovers, parties, nightlife, and maybe even romance, unlike any other she's ever had.

Based on the novel by Winifred Watson, "Miss Pettigrew Lives for a Day" has two saviors in the form of Frances McDormand and Amy Adams. McDormand brings life, wisdom and occasional naiveté of her foreign high-society surroundings to the part of plainly dressed, middle-aged Miss Pettigrew. Always seeming to have devilishly squirrely thoughts racing around in her head, Miss Pettigrew is a wry protagonist who wouldn't be nearly as notable were it not for McDormand's on-target reading of the character. As Delysia Lafosse, Adams is a joy to behold, juggling great comic sensibilities with a touching emotional undercurrent. To the men in her life, Delysia puts on a sure-footed front, but the broadness of her brassy character gradually grounds itself as the viewer learns of the desperation and insecurities she masks within. Adams is up to the challenge, making Delysia far more than just a hollow-headed caricature. The friendship that forms between Miss Pettigrew and Delysia is the soul of the picture.

Less impressive is the plot that these two fresh personalities are stuck in. The romantic quadrangle Delysia is faced with is plodding and one-note, as is her moral quandary over whether to choose someone for what they have or for who they are. Since Phil and Nick are written as shallow cads and Michael as a nice guy with honest feelings for Delysia, it is obvious who she is going to ultimately choose to be with. Unfortunately, even her relationship with Michael, played adequately by Lee Pace (TV's "Pushing Daisies"), isn't developed enough to sense any substantial history between them. Only a duet they perform near the end fulfills the requisite chemistry, but that can't make up for the silly screwball scenarios of the last hour that have kept them from building the depth and nuance necessary to care about the outcome. Likewise, Miss Pettigrew's tentative romantic subplot with fashion designer Joe (Ciarán Hinds) is appreciably low-key but perfunctory. As Joe's chilly fiancée Edythe, Shirley Henderson (2005's "Harry Potter and the Goblet of Fire") brings a sense of forlorn humanity to an otherwise shrewish role.

"Miss Pettigrew Lives for a Day" is terminally pleasant. Granted, pleasant isn't a bad thing, but the film calls for a looser, more wild side that never quite comes. Because of this, and because the multiple love stories and "be-true-to-yourself" message don't bring anything new to the equation, the picture's impact is marginal at best. Frances McDormand and Amy Adams are splendid performers who devour their roles, but their ample contributions aren't enough to stop "Miss Pettigrew Lives for a Day" from becoming a temporarily diverting, instantly forgettable bag of cinematic cotton candy.