It’s hard to say whether Amy Adams embodies a Disney heroine more in Enchanted when she’s rendered in cel animation, or when she’s wandering around New York City. In the opening sequences, she provides the voice for Giselle, a maiden in the fairy-tale land of Andalasia dreaming of her true love’s kiss. Her woodland friends flit about her in familiar fashion, but are unable to help when the wicked queen (Susan Sarandon) plots to send Giselle away so she won’t marry her stepson Prince Edward (James Marsden) and send her from her throne. One tumble down a magical well later, Giselle emerges from a manhole in the middle of Times Square—in the flesh.

And it’s here that Adams’ performance becomes something unexpectedly delightful. She cocks her wrists and curls her fingers in gleeful anticipation; she tips her head while speaking from the heart; she beams radiantly at every kind face and kinder deed. Adams’ Giselle moves through the harsh big city like a girl raised in a cave with nothing to teach her about human behavior but DVDs of Cinderella, Sleeping Beauty and Snow White and the Seven Dwarfs.

As romantic comedies go, Enchanted is simple, lightweight stuff—and also something of a missed opportunity. Writer Bill Kelly (Premonition) provides a simple foil for Giselle in Robert (Patrick Dempsey), a single dad who—in case his wife’s abrupt cut-out wasn’t enough to inspire cynicism about happily-ever-afters—also happens to be a divorce lawyer. The collision between these two mind-sets—the hopeless romantic vs. the no-hope for romance—finds a safe middle ground, and it’s equally safe about exploring its heroine’s fish-out-of-two-dimensions status. Perhaps afraid to skewer a Disney-fied world view too strongly, Enchanted opts for a few simple (and occasionally risqué) gags and the cutesy hijinks of Giselle’s anthropomorphized chipmunk pal.

In fact, the film’s only truly inspired mash-ups between Giselle’s world and our own come during the musical numbers—and they’re so inspired that much of the rest of the film feels inert by comparison. Director Kevin Lima turns to veteran Disney composer tunesmiths Alan Menken and Stephen Schwartz for a series of terrific songs, two of which energize the live-action sequences. In the first, Giselle turns to critters to help tidy up bachelor Robert’s apartment—and since this is the city, she has to make do with rats, pigeons and cockroaches. The other finds Giselle bounding through Central Park accompanied by rhythmic street musicians, spreading spontaneous production numbers wherever she goes. Dempsey’s incredulous reaction takes capture the ridiculousness of Giselle’s cartoon optimism—as well as its infectious appeal.

It really is a shame that Disney didn’t trust the strength of its brand enough to give Adams a richer context in which to work. The nods to earlier classics are here, both visually (the Maleficent-esque look of Sarandon’s evil queen) and in off-hand references (the Bella Notte Italian restaurant where Giselle and Robert share their Lady-and-the-Tramp first date, minus the spaghetti). It merely feels slight and a bit timid, even when Giselle takes sword in hand for a gender-bending rescue of her true love.

Fortunately, Adams’ performance is strong enough to rescue the film itself, as she navigates the tricky territory between endorsing Giselle’s swooning innocence and recognizing her emotional immaturity. While the story doesn’t know quite what to do with her evolution from cartoon to human being, Adams seems to. And she certainly seems to understand that a character who has spent her life in a hand-drawn fantasy world needs to move in a very particular way. Marsden does energetic work as the pose-striking prince—between this and Hairspray, who knew the stolid guy in the X-Men movies had this much personality?—but he creates his character almost entirely through exaggerated line readings. Adams doesn’t just talk the cartoon talk; she walks the cartoon walk.

ENCHANTED

*** (three out of four stars)

Starring: Amy Adams, Patrick Dempsey, James Marsden.

Directed by Kevin Lima

Rated PG.