Amy Minsky (Melanie Lynskey) is a 30-something divorcee who's moved back into her parents' home: sleeping on a foldout couch, wearing the same grubby red T-shirt day after day, sitting mesmerized in front of the TV.
She's depressed, aimlessly floating through a shadow of a life. "You're living here," says Amy's forthright mother (Blythe Danner).
"I'm staying here," Amy softly corrects her, clinging to the idea that somehow things might change. The end of her marriage came to her like a sudden electric shock; she doesn't know when she might recover.
"Hello I Must Be Going" (the title comes from a Groucho Marx song, in a movie Amy aimlessly watches) is hard to characterize.
It's part drama, part offbeat comedy, part late coming-of-age, part romance. (Amy surprises herself by becoming involved with a local 19-year-old, played by Christopher Abbott; they have an unexpectedly charming chemistry.)
But it's primarily a low-key but riveting star turn, from an actress who's long waited for one.
Lynskey burst onto the scene as a teenager opposite Kate Winslet in "Heavenly Creatures" nearly two decades ago, and has since built a career playing small, memorable roles in other people's movies.
Now she's finally been given one of her own, and she saunters off with "Hello I Must Be Going" with a sweet, quiet confidence.
Lynskey lets us see, from deep within Amy's fog, an instinctual desire to please, and a sense of innocent wonderment at how she could possibly have gotten into such a mess.
A late scene with the ex-husband (Dan Futterman, wonderfully self-absorbed) is a small master class in acting: We watch Amy realize what she wants, and finally place her past — which she's been wearing, like that T-shirt — behind her.
You feel, watching this movie, as if you've made a friend; at its end, you wish her well.
"Hellow I Must Be Going," is rated R for language and sexual content; running time: 94 minutes.