Sutter Keely (Miles Teller), the adolescent hero of James Ponsoldt’s gentle teen seriocomedy The Spectacular Now, is one of those types who seems permanently glued to his preadult world in Anytown, USA. At 17 years old, he can’t picture himself ever doing anything other than Mickey Mousing classes, working at his part-time job in the local suit store, partying with friends, indulging in underage drinking, and dating around. He’s a real character — a dyed-in-the-wool b.s. artist and charmer who has his timing and his “lines” down pat as he glides through crowds at parties, attempting to woo his classmates and pick up gorgeous women. When we first meet him, he’s still struggling to come to grips with a recent breakup with his dynamic ex-girlfriend Cassidy (Brie Larson). He awakens after a night of heavy drinking on a suburban lawn, where he’s discovered by another classmate, the beautiful Aimee Finecky (Shailene Woodley). At first glance, she’s everything Sutter isn’t: a committed student, a wallflower and social outcast, a virgin with no relationship history, as sincere and from-the-heart as Sutter is full of hot air. But in time, the two begin spending their days together and, upon learning that they have a great deal in common, gradually become the most important individuals in each others’ lives.

The central conflict of the movie involves Sutter’s immaturity. Stuck in the rut of arrested adolescence, he has apparently given no thought to growing up, to taking control of his life and abandoning a juvenile mind-set. While most of us see high-school life as a means to an end, Sutter would prefer to stay there perpetually, in the “spectacular now” of the title; at one point, he informs Cassidy that he has everything he could ever want or need right there in town — a home, a job, a car. Aimee challenges that sense of security: She’s the first person in his life who has ever made him want to think about grander things.

Many films rise and fall on the strength of their approach, and for at least part of the way, this picture nails the ideal tone. Sutter could have easily come across as a real cad, especially given his social manipulations, but this never happens. Ponsoldt and his two screenwriters, Michael H. Weber and Scott Neustadter (500 Days of Summer), strategically include scenes at the beginning that unveil the teenager’s naiveté, suggesting that he’s basically an innocent whose attempts to curry favor with those around him (women and men) often backfire rather than help him succeed — as when Sutter tries to charm two girls at a party, and instead comically falls on his face. Above and beyond that, the casting of Teller was an inspired move: The young actor enables us to see through the veil of the character’s party-happy mind-set to the massive vulnerability and fear that lie beneath. Woodley was an equally ideal choice for Aimee; the actress plays her character as so open-faced, so guileless, so unassuming, that you can instantly believe in her ability to strip Sutter’s defenses and touch his heart sans any conscious awareness of what is happening. The result, in the early stages of the film, is one of the most affecting movie love stories in a very long time, with characters we begin to care about passionately and intensely.

If the picture began and ended there, perhaps it could earn its right to classic status as Say Anything and 500 Days of Summer did. Unfortunately, this film has a flaw — a grave one in fact — involving Sutter’s drinking. Bear in mind that this kid is underage — and he doesn’t simply drink on occasion; he constantly has a flask of some unspecified hard liquor in hand. While driving, at his job, at parties. He drinks so much that if he lit a cigarette, he would combust. The movie lays out all of the telltale signs of a serious, clinical alcoholic, but never deals with it satisfactorily or intelligently. The romance with Aimee eventually begins to strain credibility for this reason: We learn that her father died of an overdose of painkillers, so she of all people (a young woman who is a sharp, articulate, and perceptive character) should have warning signs going off right and left in her head, and there is absolutely no way under the sun that she would so readily accept a liquor-filled flask from Sutter as a gift and begin drinking steadily herself. There are also two unforgivable developments in the final act involving alcohol, the most critical of which involves a serious quarrel between the two lead characters. What eventually happens in tandem with that argument is so extreme and severe, we can’t believe for a second that Aimee would be anything less than enraged at Sutter to the point of permanently severing all ties with him. Instead, she seems to lack any trace of ire, and that isn’t merely difficult to swallow, it is ludicrous.

In the process, then, the film eventually begins to work against itself and erodes the goodwill that it had earned: Your sympathies continue to lie with this couple, and you realize that you’ll feel seriously cheated if Ponsoldt and his scribes don’t provide an optimistic, hopeful ending, but at the same time, the script sets the bar far too high in terms of the issues that Sutter needs to overcome. In addition to harboring a serious need to check into Betty Ford, the character continues to slip in school to the point of almost complete disaster; in fact, everything about the movie’s interior logic suggests that it’s setting up a tragedy. The filmmakers try to save the day and the character with a reassuring last-minute pep talk from his mom (Jennifer Jason Leigh) designed to bring him back to his senses, but it’s all too little, too late; by then we’ve already given up on the story and can’t help but feel that Sutter and Aimee deserve to be in a far more intelligent and thoughtful movie.