In "Smashed," Mary Elizabeth Winstead is Kate, a high-functioning alcoholic who manages to be a capable first-grade teacher by day and a tipsy karaoke clown by night.

Kate's problems with impulse control come into focus quickly, when a drinking companion offers her a hit of crack and she can't think of a reason to decline. The film could be pigeonholed as an addiction drama, and it is certainly serious about Kate's struggle with her disease. Written by Susan Burke, who clearly knows more about these stories than is taught in screenwriting class, it conveys a rare depth of understanding and compassion for its protagonist.

Winstead is an immensely appealing and subtle talent, and her performance is a careful balancing act. We can see why her co-workers like her, how she can fool them with her honest searchlight eyes, and why her husband and drinking buddy, Charlie ("Breaking Bad's" Aaron Paul), just wants their nightly booze- fueled Mardi Gras to continue. Drinking makes her a silly, flirty, kittenish little charmer. Until she's a train wreck. She's very good at showing us when a drink is a shot in the arm, and when it's a punch in the face.

One morning, after emptying the contents of her stomach into the wastebasket in front of her class, Kate improvises a morning sickness excuse. The deception, and the inevitable follow-up lies, complicate her relations with the staff. When the vice principal (Nick Offerman of "Parks and Recreation") sees through her ruse and nudges her to join him in A.A., Kate takes a few small steps toward sobriety.

It's a slippery path, even with good intentions and the help of a sympathetic sponsor ("The Help's" Octavia Spencer). Charlie still enjoys getting drunk. He enjoys Kate when she's drunk. And Kate's only way out of her hole may cost her career.

Modestly scaled but sure-footed and entertaining, "Smashed" gives us the sense of life unfolding before our eyes. It invites us to invest our hopes in someone who may disappoint us. It never tempts us with the promise of a forced happy ending. Kate's grip on her impulses is shaky, and pulling for her recovery is as gripping as watching a tightrope walker. She's bright, she knows drinking may destroy her, but she's hooked. The film sees much to criticize about her but also much to love.

Winstead, who rose through the ranks in horror fare, is superb as she battles demons of a different kind. She delivers a sublime performance, capturing both the high spirits a bender can provide and the disastrous depression that follows. She skillfully delineates the difference between being in high spirits and being wasted. With surprising humor and a refreshing lack of sentimentality, she draws us into the life of a woman doing her best to beat a crippling addiction.

Director/co-writer James Ponsoldt frames her in long, unbroken takes. We get that rare sense of seeing a great actress in the first role that really taps her talent. Look for Winstead on a red carpet in Los Angeles come Oscar season.

Colin Covert • 612-673-7186