A hardened misanthrope who has just sent her much younger lesbian lover packing, Elle Reid is ready to sink back into solitude, the simple life. She has cut up her credit cards, paid off her bills. She'd like everyone to leave her alone.

And then, someone's at her door.

In Grandma, Paul Weitz's rich, biting character study set in some out-of-the-way corners of L.A., there's no escaping the past, the present, or the curly-haired granddaughter on the front steps who needs help with her future. Desperately.

With Lily Tomlin at the top of her game as Elle - a fired-up feminist, prize-winning poet, failure as a nurturer - Grandma moves through a series of chapters ("Endings," "Ink," "Apes," and three more) and a series of confrontations and uncomfortable, often comic, exchanges.

Sage (the very good, kewpie-dollish Julia Garner) is a high-schooler who has gotten pregnant. She can't keep the child. She can't tell her mother. She doesn't have the $600-plus to pay for an abortion.

Elle doesn't have the money, either. She may be debt-free, but she's also essentially cash-free, at least for the time being. So, Elle ushers Sage into a not-exactly-trusty old Dodge and off they go on their crowdfunding mission. Well, not a crowd, but an small clutch of friends, eccentrics, exes.

And, yes, Sage's boyfriend - an eye-rolling deadbeat played with a convincing lack of empathy by Nat Wolff. He gets his.

Grandma functions like a low-mileage road movie, with its front-seat protagonists learning about themselves, about each other, and about the people in their lives as they drive around town.

Loss looms large in Elle's life. Her longtime companion, a woman named Violet, is gone, and the emptiness still hurts. Sage is just a kid, figuring out what she wants - but she knows that, right now, having a baby would just not work. The hot-button issue of abortion is handled matter-of-factly, honestly, and Elle has a thing or two to say to the protesting mother and child in front of the clinic. The protesters have their say, too.

There are some terrifically strong scenes and terrific actors contributing to them. Marcia Gay Harden, with her headset and her treadmill desk, is nutty and real as Sage's over-caffeinated, workaholic mom - and Elle's estranged, grown-up daughter. Sam Elliott brings palpable hurt and heartbreak to his short but riveting turn as a man once deeply in love with Elle, whom he now finds standing across from him in his handsome house, asking for money.

"I'm a horrible person," Elle cautions Olivia (Judy Greer), the girlfriend she's breaking up with, and evicting, as the movie begins. But Elle, of course, isn't horrible at all. She's funny. She's smart. And when it matters most, she's there for her loved ones.

Even if her loved ones weren't even sure she was capable of the emotion.