Illinoise, which opened Thursday at the Park Avenue Armory, is a sui generis multidisciplinary marvel that suggests new possibilities for both dance and theater. Justin Peck, resident choreographer at the New York City Ballet and a Tony winner for Carousel, has delivered an absorbingly expressive work for 12 young dancers inspired by Sufjan Stevens’s acclaimed 2005 concept album Illinoise. It’s not an obvious choice for stage adaptation as the collection of tunes about the Midwestern state combines elements of indie folk, alt rock, and classical music with his bold use of orchestral arrangements (which Stevens played himself with multi-track recording).

Stevens has a flare for bringing symphonic heft to popular music, and his music gets a full soundscape treatment with an 11-member band — 14, if you count the three butterfly-wing-wearing instrumentalists who also serve as vocalists on all of the album’s tracks. (The flame-haired Shara Nova is particularly stunning, delivering sustained high notes that are ethereal without dissipating into breathiness.) But the production also benefits from a narrative frame supplied by Pulitzer-winning playwright Jackie Sibblies Drury (Fairview) that elevates Stevens’s material from more than just a gathering of songs loosely bound to the state that was home to John Wayne Gacy Jr., Superman, and Chicago’s Sears Tower.

We’re introduced to a posse of young people who gather around a campfire to swap stories — it’s a familiar rite of passage for Americans on the cusp of adulthood and it provides a storytelling spine that is sturdy enough to sustain a 90-minute show without the introduction of actual dialogue. It also allows the company to re-create the hodge-podge range of the album’s tunes, which don’t always line up with the onstage action in literal ways. There’s a yarn about zombies, another about the serial killer Gacy, and a third about the town of Jacksonville featuring a duel between a modern dancer (Rachel Lockhart) and an enthusiastic tapper (Byron Tittle) that is both invigorating and exhausting to behold.

Ultimately, though, the campfire cornucopia cedes to a single sustained story from a young gay man named Henry (Ricky Ubeda) — identified on the giant billboard onstage as well as the elaborate multipage journal that bookends the program. He recounts his upbringing in a small Midwestern town, his romantic pining for his best friend (Ben Cook), their escape to Chicago and later New York City, and then the pal’s return to his cancer-stricken high school girlfriend (Gaby Diaz) followed by a stark descent into acute depression. This halting adolescent romance forms the core of the story, and Peck gives the emotional undercurrents a physical form in some of his finest choreography.

There’s a lovely trio in which Cook’s character is drawn between the two teens claiming his attention and affection — with Ubeda’s Ricky articulating all the longing and disappointment of any adolescent who finds himself relegated to third-wheel status. In other numbers, we get unison pirouettes to underscore a relationship that’s in sync — or sharp punches of the hands, elbows and legs to suggest the anguish of disappointment and isolation. There’s a fluidity to the movements here, with the entire company accentuating the story beats as well as smoothing the transitions with handheld lights and other props. (Adam Rigg designed the striking graffitied set, sharply lit by Brandon Stirling Baker, while Reid Bartelme and Harriet Jung designed the Urban Outfitters-inspired costumes).

Illinoise makes a striking case for how modern dance, set to contemporary music, can tell a story that speaks to generations of audiences without preaching or condescension.