At first glance, “My Old Lady” is a neatly packaged film, sure to serve as a nostalgic “Philomena”-like trip down memory lane. But, there is more to “Lady” than meets the eye. Israel Horovitz’s film, hitting theaters today, reveals itself as a complex, intimate journey grounded by its unexpected lead performances.

In what appears to be a farcical premise, Madame Girard (Maggie Smith), a sassy old lady, is forced to live with Mathias (Kevin Kline), a cynical stranger, in Paris. From there, the film evolves into something much more meaningful. Although “old” is easily pegged as the film’s buzzword, it is actually about youthful relationships. While each character places importance on the passage of time, the film itself supersedes their silly notions. “Lady” preys on the common saying that age is just a number, but it does so subtly.

Madame Girard’s daughter Chloé (Kristin Scott Thomas) and Mathias are both full-fledged adults — seeing out the final years of their 50s — but the pair behaves in a way that is defiantly immature. Chloé carries on an affair with a married man, and the penniless Mathias drinks himself into a stupor every night. But, despite the obvious contradiction of their age to their behavior, time and again their differences are brought to the fore. Madame Girard wonders aloud how Mathias could possibly have so little to show for the significant amount of time he has been alive. And Chloé, upon being told she is beautiful, immediately corrects her suitor, telling him that she is not beautiful because she is growing old.

Catering to “My Old Lady’s” neatly packaged facade, Thomas’ Chloé is a middle-aged French speaker — a role that, at first, seems to be a case of severe typecasting for Thomas. But  with a beautiful, nuanced performance, Thomas makes Chloé feel like a fresh, new character. In fact, Thomas’ presence in “My Old Lady” nearly relieves the commercial exhaustion of her constant pairing with France. Thomas does not throw any new punches, but her acting style, surprisingly powerful in its subtlety, adds greatly to the film. Her performance, along with those of Kevin Kline and Maggie Smith, is essential to “My Old Lady.”

All of “Lady’s” surprising facets point to the skill of its first-time director, Israel Horovitz. Adapted from Horovitz’s own long-running play of the same name, Horovitz’s talent is apparent in both the tale played out on screen and the unseen details. While many elements of the film deserve a lengthy victory march, the successful translation from stage to screen stands as the crux of achievement. “Lady” is a seamless adaptation. Somehow, “Lady” skirts past the problems of making something dramatic into something cinematic, presenting a riveting, cliché-defying directorial debut.

A version of this article appeared in the Wednesday, Sept. 10 print edition. Email Isabel Jones at [email protected].