It's just that sense of structure and carefully calibrated warmth that Grace so intuitively and expertly gives the kids under her care, a ragtag group of miscreants and left-behinds that includes Sammy (Alex Calloway), a redheaded boy who, when he's not playing with his cherished dolls, flies into periodic rages and tries to run away.
But Grace isn't quite as practiced in self-care, a fact that becomes clear when her interactions with a co-worker named Mason (John Gallagher Jr.) become more complex, and when a new resident named Jayden (Kaitlyn Dever) pushes some of Grace's more problematic buttons.
As those two strands of the story converge, the plot of "Short Term 12" veers dangerously close to schematic, Screenplay 101 melodrama — a weakness that stands out in even sharper relief within a bracingly loose, improvisatory aesthetic style.
The most exhilarating things about "Short Term 12" aren't the plot points but the myriad revelations that transpire between the characters moment by moment, whether in highly charged encounters in the facility itself or in more gentle interactions when Grace is at home (and only slightly less emotionally armored and wary).
Larson, a natural beauty who also can be seen in the similarly accomplished teen romance "The Spectacular Now," is receiving deserved buzz for her portrayal of Grace, who joins Olivia Wilde's leading lady in the romance "Drinking Buddies" as a refreshingly new kind of feisty, flawed screen heroine.
But for my money, the most startling performance among many in "Short Term 12" comes from an unknown young actor named Keith Stanfield, whose haunting portrayal of a terrified 18-year-old about to age out of the home recalls Matt Damon's similarly expressive breakout performance in "Courage Under Fire."
While idealized versions of childhood and family play out on television behind him, Stanfield's Marcus bears stoic witness to the ways he's been betrayed by adults, most fiercely during a devastating rap about his mother.
Terms like "healthy boundaries" and "it takes work" are thrown around with glib promiscuity in a culture awash in self-help clich?, but "Short Term 12" reminds us why they're still valid.
Where some viewers might think of it as a social-problem film, it's far better understood as a romance.
"Short Term 12" is that rare movie gutsy enough to tell the truth about love: that it's not a poetic longing or a magical-thinking happy ending, but a skill. And, the film suggests, we all have the capacity to learn it.