La La Land begins with such an ecstatic rush of joy—and ends with such a gloriously bittersweet flourish—that you kinda can’t blame the film for sagging a bit in the middle. Damien Chazelle’s intricate, wondrously executed modern musical is a sight to behold: sad and happy, funny and romantic, technically dazzling. But, like the classic musicals of old that the film pays homage to, La La Land is not perfect. There are moments, though, when it comes close, so soaring and gorgeous that tears spring to the eyes. And that might be enough.

The framework of the film is fairly simple. A girl (Emma Stone) meets a boy (Ryan Gosling), and a prickly courtship turns into a swooning romance, which turns into, well, something approaching real life. The girl, Mia, is an aspiring but struggling actress, while Sebastian is a bitter jazz pianist thwarted by his own purism. They live in Los Angeles, which—yup, you guessed it—is really the third character in the film. (Apologies.) The City of Angels is saturated and serene as the beginning of Mia and Sebastian’s romance sparkles with song. These two dreamers yearn for fulfillment in their respective fields while falling into each other; Chazelle weaves in winsome compositions by Justin Hurwitz, with mildly poetic lyrics by Broadway duo Benj Pasek and Justin Paul. Deftly staged by Chazelle and lavishly shot by Linus Sandgren, the first third of La La Land promises a film of almost otherworldly style and clever heart.

But then the next stretch begins. As Sebastian finds a successful if not entirely satisfying career in music, and Mia tries to put together a one-woman show, the music suddenly stops. Almost literally. While we do see Sebastian playing with his band (led by John Legend), the musical-ness of La La Land drains away, ceding to a basic relationship story we’ve seen many times before. There’s still enough charm innate to this project to hold our attention, but the specialness of the film’s beginnings is sorely missed. It’s as if Chazelle ran out of steam, figuring a regular old romantic dramedy would suffice until . . .

The ending. Oh, the ending. In its last 20 or so minutes, La La Land nearly washes away the problems that just came before. Stone delivers a lovely 11 o’clock number about the quaint, dreamy nobility of the creative life, then hands the baton to Chazelle, who offers up a whopper of a final musical montage. With its hat-tips to old musicals and its reverence for jazz, Chazelle’s film is a loving appreciation of those art forms of yore, and a rather impassioned plea to keep them alive. There’s an urgency to the film just underneath all its pretty, nostalgic finishings. But La La Land understands that not everything can be saved, that some grand things have to go the way of the dodo as the world spins on. In that spirit, the film ends with an affectionate, wistful kiss goodbye, a sublime sequence that might guarantee the film’s good fortune at the Oscars.

Speaking of the Oscars: though the direction and design are fabulous, I think the film’s biggest asset is Ms. Stone, who gives a performance of such natural intelligence and warmth that I’d have to imagine she’ll be a very strong awards contender this year. (She’s got the musical/comedy Golden Globe already in the bag at this point.) But besides that cynical odds forecasting, this is simply a huge performance for Stone, who has always had an abundance of appeal but has had trouble of late finding a role, and a film, worthy of her abilities. She’s certainly found it in Chazelle’s movie, giving a star turn of the highest magnitude—while singing (convincingly) and dancing, even. It feels like she’s arrived all over again. Gosling is certainly good too, but his performance is a bit more familiar, and his singing is not up to Stone’s level. Still, he and his glowing co-star once again have a witty, winning chemistry.

It’s awfully surprising, in a pleasant way, to see Chazelle working in this mode. His previous film, the Oscar-winning Whiplash, was so butch and so mean that he seemed destined for a (fruitful) career in movies about hard-charging men monolithically pursuing some goal. But maybe it really was the music and not the rage that fueled Whiplash, as Chazelle shows a real penchant for the sweet and sentimental in the appropriately named La La Land. Sure, the movie is a little directionless in parts—but when it works, it really works. And it’s so admirably sincere: an air of smugness or self-satisfaction never enters the picture, though this movie easily could have been smug or self-satisfied. In a year of difficult things, La La Land does the genuine, generous work of lifting hearts, urging us to remember how lovely it is to love.