The prologue of Niall Johnson's dark, wry picture reveals the past of the dear, hardly senile woman, regarding her husband and her mistress. Now, think of Nanny McPhee with much more of an edge to it.
The quaint hamlet of Little Wallop, with a population that could fill a busy convenience store, is where Grace is retained by its vicar, Walter Goodfellow (Roman Atkinson).
Goodfellow has much on his mind, perhaps obdurate towards his family. Wife Gloria (Kristin Scott Thomas) is bored and uptight, while his teenage daughter Holly (Tamsin Egerton) has pent-up desire. And, his sensitive son (Toby Parkes) isn't having fun at school constantly being picked on.
Grace's long term "asylum" ways reappear as she has a surprising connection to the Goodfellows. In a drastic way, Keeping Mum has family values on its mind, as the efficient housekeeper, acting like an enzyme, is able to do more than the requisite chores.
If John Waters had his way with Waking Ned Devine, Grace might have been just as engaging as she is here, even without a heart of gold. Some may find the underpinnings at odds with the message coming from the vicar's reassessment of his vocation.
Still, there's a spry pungent aroma that the cast delights in, and Smith, again, is convincing in providing dysrhythmia to what is, in fact, a heartwarming tale. Grace's manner elicits goodness with the same modesty of "let's have a cup of tea" seen in the powerful drama Vera Drake.
Keeping Mum may not be that revelatory, but Patrick Swayze is, at least in one scene, opposite Scott Thomas, as a sleazy golf pro. Atkinson's milquetoast vicar is capable of more than deadpan befuddlement, and the actor, well known for the role of Mr. Bean, rises to the occasion. And before Holly learns something important on the road to maturity, Egerton definitely livens up the screen with her bold tenacity.