In a much-loved 1961 cover, Etta James famously sang, “I want a Sunday kind of love / A love to last past Saturday night.” Working its way through into one of the many warm, mesmeric scenes of Lone Scherfig’s new movie, “An Education,” the song becomes emblematic of the film itself. The melancholic strings and James’s wistful vocals are echoed in, and intertwined with, the sixties chic and rainy day intimacy of Nick Hornby’s latest screenplay.

Based on the memoirs of Lynn Barber, a renowned British journalist and less-renowned author of the seminal “How to Improve Your Man In Bed” manual, “An Education” focuses on the late adolescence of Jenny (Carey Mulligan), a London schoolgirl who enters a reckless romance with an older man. Hornby imbues the film’s script with his trademark wit and fast-paced plot development, but despite his compact and compelling writing—recognizable from earlier films like “High Fidelity”—he reveals a weakness for tidy resolution that foregoes the film’s darker, more powerful aspects.

Within the first 10 minutes of the film, 16-year-old Jenny meets 30-something David (Peter Sarsgaard). In the vein of Hugh Grant—another middle-aged Hornby bloke—David is armed with a charming smile, a fast car, and an affable worldliness. These qualities provide Jenny with an appealing escape from her oppressive world of resumé building and underwhelming pubescent suitors—a world entirely governed by her overbearing father, Jack (Alfred Molina).

The dull grays and whites of Jenny’s school and home life soon explode into the exuberant reds, golds, and blues of David’s seemingly fairy-tale existence. The stylish cinematography carries the film, subtly accommodating Hornby’s riotous sight gags while capturing the sophistication of the leads’ cosmopolitan adventures. Lush, gorgeous shots refresh the film’s rather familiar coming-of-age storyline and make the film’s central tension feel new and urgent.

In one beautifully constructed scene, David picks Jenny up from her house, playing his cool confidence off Jack’s bumbling attempts to control a daughter whose intelligence surpasses his own. Jenny joins David and his two elegantly detached peers—Danny (Dominic Cooper) and his glamorous girlfriend, Helen (Rosamund Pike)—for “supper” at one of London’s most posh restaurants. Here, the aforementioned “I Want a Sunday Kind of Love” rushes through the speakers, enveloping Jenny’s breathless contentment. The first three-quarters of the film are comprised of many scenes like this, delivering genuine humor, stunning cinematography, and well-constructed narrative at the same time they expose the sad nostalgia of growing up.

Helen, whose vapidity and self-satisfaction embody the concept of ignorant bliss, serves as one of two models for Jenny as she contemplates her future life. The other is her bookish teacher, Ms. Stubbs, played by Olivia Williams (who essentially reprises her role as Rosemary Cross in another coming-of-age classic, “Rushmore”).

When Helen encourages Jenny to update her wardrobe, pointing out that David would gladly buy her anything she wanted, Jenny is confused: “Why would David want to take me shopping?” This kind of natural, charming innocence keeps the audience sympathetic toward Jenny despite her vain, often painful attempts to seem old and sophisticated, the most embarrassing of which are her frequent, unprovoked outbursts of French.

Carey Mulligan—whose most notable screen credit to date is as one of the minor sisters in “Pride and Prejudice”—shines in her breakout role as Jenny, portraying a wealth of emotion, conflicting desires, and youthful rebellion with the subtlety and intelligence of a much more experienced actress. David’s emotions dictate the tonal shifts of the film, and Sarsgaard lives up to this responsibility with his confident but gradual revelation of his character’s true nature—equal parts sparkling charm, menacing deception, and inner conflict.

In the end, “An Education” asks all the right questions but yields too few answers to satiate the promises of its brilliant first three-quarters. When Jenny and David go to Paris together, the film temporarily drops all its weight and scrawls a breathless love letter to the city and the good looks of the protagonists. The conclusion—which should either re-pose the film’s questions or provide some answers—conveniently forgets them, summarizing the next four years of Jenny’s life in a clichéd voice-over that almost kills the movie. Still, while it lasts, the film is breathtaking, an achingly beautiful tribute to a half-imagined time when even the most devious among us knew how to cut a rug and fall in love.