Last fall I saw the Ballet 422 at the Tribeca Film Festival, which is now coming out in theatres. I can say that it is one of the finest dance films I’ve seen, far surpassing the director Jody Lee Lipes’ previous foray into the genre, New York Export: Opus Jazz. Heretical as it may sound, I found it better than Frederick Wiseman’s documentary La Danse, the film it most closely resembles, partly because much of the choreography in that documentary was so dire. (At almost three hours, it was also excessively long.) Like Wiseman, Lipes doesn’t identify the characters, my one complaint. But he does well to focus his film on a single subject, the creation of a ballet, from start to finish. It’s a nailbiter.

The ballet is Justin Peck’s Paz de la Jolla, made for New York City Ballet in 2013. (It was the company’s 422^nd work, hence the movie’s title.) I was there for the première in January and can attest to the fact that it was a pretty thrilling event; the ballet is fast-paced, full of detail, imaginative, and deeply musical. It also includes a real coup, a convincing underwater dream-ballet. A couple (Amar Ramasar and Sterling Hyltin) falls asleep on the beach; the woman rises and is drawn ever deeper into the waves. The dancers’ bodies, intertwined and intricately patterned by Peck, become the sea’s eddies and foam. Peck has a knack for creating vivid, and very specific, imagery with groups of dancers. It’s not just pretty pretty.

The film shows the process from the very beginning, as Peck works alone in the studio, listening to Bohuslav Martinu’s Sinfonietta la Jolla on a boom box and video-taping short phrases of movement with his IPhone. These ideas are translated into sketches drawn with stick figures and dots representing floor patterns and shapes. There’s no talking, no voiceover, just work. Rehearsals are periods of intense creativity, experimentation, and problem-solving, but also of close observation and rigorous imitation. Peck doesn’t let anything slide. In one scene he corrects a young dancer who is trying to recreate a complex set of movements for the arms. She does it again and again. Each time he says “no,” not unkindly, but unwilling to settle for anything less than what he has in mind.

The sheer amount of work is staggering. At several points in the film, one or another dancer, including Peck (then in the corps de ballet) looks almost inhumanly tired. The work is also mentally exhausting, requiring precise imitation, memory, analysis, instant playback. In one of the most fascinating moments in the film the dancers do nothing more than count out the beats in the music, figuring out how the steps fit into the notes. There’s no artificially-constructed melodrama here—the drama is the work itself.

We see fabrics being dyed and cut, hairstyles being sprayed rigidly into place, tempi adjusted by the conductor, musical dynamics discussed, lights experimented with. (The one thing we don’t see, oddly enough, is the company’s artistic director, Peter Martins.) I chuckled at the sight the mustaches for Vienna Waltzes, all pinned up on a board, each labeled with a dancer’s name. The film-makers have been given remarkable access, even to the inner sanctum of company class, where wan-faced dancers in motley rehearsal gear sweat and go through their daily paces. The backstage areas are unadorned, even dingy. This is the factory-floor where illusions are created.

Peck is involved in every aspect of the production: costumes, lighting, musical interpretation. Calm, blank-faced, mouth slightly open, he watches, scouring details, and then goes home—we see him taking the elevated subway line to his small apartment where a portrait of Jerome Robbins hangs on the wall—to watch rehearsal videos and fine-tune some more. At only twenty-five (now twenty-six) he shows surprising self-assurance and composure. The only time he seems to lose his nerve is during a slightly awkward interaction with the orchestra—certain boundaries are not be crossed.

As opening night approaches, tension mounts, faces become strained. It’s surprising how few smiles one sees. A few people manage to keep their good humor and spread it around: Cameron Grant, the pianist, with his perfect hair and calm demeanor, is an unflappable, fatherly presence. Amar Ramasar, the male lead in the ballet, seems to be in a perennial good mood. Moments before going onstage, his tense ballerina asks if they should run through their duet one last time. He smiles and says, with gusto, “don’t worry, I’m just going to grab those hips.” Her jaw relaxes ever so slightly.

Ballet 422 is about as close as many of us will ever get to the creation of a new work of art. The dancers are revealed for what they are; phenomenal technicians, willing and intelligent collaborators, tired bodies. At the screening I attended, the dancing, especially by Tiler Peck (no relation) drew gasps from the audience. But another thing also shone through: a kind of loneliness at the heart of the process. At the end of the day, it all comes down to one person, creating something out of nothing.