Salma Hayek is virtually unrecognizable in “Beatriz at Dinner,” a sad-eyed parable in which she plays a massage therapist and healer in Southern California whose car breaks down at the home of a wealthy client, pushing her into an Alice-like plunge through the looking glass of race and class, friendship and professionalism, and liberal earnestness and hypocrisy.

As the movie opens, Hayek’s title character can be seen praying in front of a shrine that includes photos of her ancestors and a beloved pet goat, whose untimely demise plays an unlikely role in the day that unfolds.

After seeing clients at a clinic for cancer treatment, she makes her way to a house call in Newport Beach, where her client Cathy (Connie Britton) lives in a sprawling McMansion with her husband, Grant (David Warshofsky). When Beatriz’s car goes on the blink, Cathy insists she attend the small dinner party they’re throwing to celebrate a recent real estate deal that Grant has struck with a developer named Doug Strutt (John Lithgow) and a young legal eagle named Alex (Jay Duplass).

What ensues is an awkward evening that only gets weirder as Beatriz, emboldened by several glasses of wine, confronts the assembled guests with their unexamined privilege and, when it comes to the aptly named Strutt, predatory pursuit of wealth and comfort.

In contrast to the brittle, superficial tribe she has temporarily infiltrated, Beatriz is a hugger, a deep empath and, when aroused, a fierce teller-of-truth-to-power. In a way, she’s Wonder Woman’s modern-day Mexican-American cousin, a woman who can’t witness injustice or pain without doing something about it, even if it’s only to raise an anguished cry.

As touching as Hayek’s performance is, “Beatriz at Dinner” too often forsakes nuance for caricature, especially when it comes to Strutt, who emerges as the one person who comprehends and even applauds Beatriz’s chutzpah, but who ultimately feels more like a convenient billboard than a fully realized, contradictory character.

Similarly, the rest of the dinner guests, who include wives played by Chloë Sevigny and Amy Landecker, never come into focus as individuals. Rather, they’re a well-dressed, indistinct mass of insensitivity and cluelessness.

“Beatriz at Dinner” is a delicate, mournful, mystical little movie about the porous membrane that defines all our bubbles, and how tenuous its surface tension can be when severely tested.