Grade: B

At age 75 Lily Tomlin gets the role of a lifetime in writer-director Paul Weitz’s “Grandma.” In truth the movie isn’t all that much—a series of sketches knitted together into what amounts to an oddball road trip. And from a technical point of view it’s no more than workmanlike. But Tomlin makes each stop along the way count.

The picture begins somewhat weakly with a breakup scene between Tomlin’s Elle Reid and her much younger girlfriend Olivia (Judy Greer), during which the older woman’s acerbic personality is in full flower. Reid, a once-famous feminist poetess now living largely on memories and occasional temporary academic appointments, dismisses Olivia as a mere footnote to the thirty-eight-year relationship she shared with the love of her life, Violet, who’d died a couple of years previously, and tells her to leave the key on the table as she leaves. Then Elle breaks down in tears as she showers, dons a cap and gown that she hasn’t worn in years, and sits down to look at photos of her and Violet.

Elle’s nostalgic journey doesn’t last long, though: she’s interrupted by the arrival of her granddaughter Sage (Julia Garner), who announces that she’s pregnant and needs $600 for an abortion. Elle quite properly asks whether the girl has thought about the consequences of taking such a step, warning her that it’s a decision that she’ll have to live with for the rest of her life; but she doesn’t try to dissuade Sage from terminating the pregnancy. Unfortunately she’s broke, having used her savings to pay off all her debts (resulting, it’s assumed, from Violet’s medical bills) and cutting up her credit cards, the bits of which now serve, she proudly points out, as a wind chime on her patio.

So they’re soon off in Violet’s old car to try to find the money. After an unfriendly encounter with a barista (John Cho) who runs a coffee shop where a woman’s health clinic used to be, their first stop is Sage’s caddish boyfriend Cam (Nat Wolff), whom Grandma coolly puts in his place with the hockey stick he’s toying with. Then they visit Elle’s old friend Deathy (Laverne Cox), a transgender tattooist who’d like to be of more help but is strapped for cash herself, and the owner of a café (Elizabeth Pena) to whom Elle hopes to sell some first-edition feminist books, until the two end up screaming at one another. (That last sequence also brings Olivia back into the picture, leading to an argument featuring insults only an academic could love, like being called a “writer in residence” to imply a lack of tenure.)

Finally Elle reluctantly goes to Karl (Sam Elliott), the man she left for Violet. A guy with multiple ex-wives and lots of grandkids, whose photos fill the walls of his handsome home, Karl still harbors a grudge over her dumping him, and in return for a loan expects more from her than she’s initially willing to give. The episode includes some unfortunately clichéd elements—like their sharing some marijuana Elle had confiscated from Cam—but overall it’s very sensitively done, with Elliott matching Tomlin beat for beat while creating layers of character within a short space of time. And given Karl’s concern for family, it ends in just the right way.

That leaves the women with no choice but to approach Judy (Marcia Gay Harden), Sage’s terrifyingly know-it-all mother, with whom Elle has a frosty relationship, no doubt because they’re both so prickly and hard-nosed. Like Elliott, Harden makes a terrific partner for Tomlin, the two lobbing Weitz’s sharp-edged lines at one another like well-seasoned tennis players slamming the ball back and forth over the net. One sees the mother in the daughter despite their differences, with Elle the cranky idealist and Harden the frustrated pragmatist but both sharing a gutsy take-no-prisoners approach to life.

It’s inevitable that “Grandma” softens toward the close—as do Elle and Judy, as they not only reconcile as best they can for Sage’s sake, and Elle in making a quick stop at Olivia’s apartment in an apologetic gesture that, for her, is quite a turnabout. But even in these closing sequences, Weitz tosses in some welcome doses of misanthropy—an encounter with an anti-abortion activist at a clinic parking lot, the mendacity of a taxi driver—that help give the film a hint of tartness even as the level of sentiment increases.

One can certainly criticize the picture for being not only so carefully calibrated a love letter to the pioneers of feminism, but one fabricated so completely around Tomlin’s own persona that one imagines she slipped effortlessly into the lead. And technically it’s no great shakes, with merely serviceable camerawork from Tobias Datum and a score by Joel P. West that pushes emotional buttons too readily. But even while recognizing the calculation behind Weitz’s method, you can’t help but enjoy the vivacity with which Tomlin brings the manipulative material to life. She works beautifully with Garner, Greer, Cox, Pena and Wolff, all of whom respond with cheekily right-on turns of their own. And when she’s coupled with Elliott and Harden, the result is pure magic.

So we should be as grateful to Weitz as Tomlin must have been when he handed her the script.