It's the evening of Thursday, April 1, and, no foolin', Broadway's St. James Theater is packed. Previews of the musical "American Idiot" started little more than a week ago in anticipation of an April 20 opening, and the theater has been close to capacity every night.

Onstage, faded rock posters and multiple TV screens provide the backdrop for 95 minutes of singing, dancing and Green Day songs. The plot centers on three young men trying to escape dead-end suburban lives. Will fails to launch even when his girlfriend falls pregnant; the other two "succeed," in a manner of speaking. Tunny winds up being seduced by a flashy military recruiter, goes to war and promptly loses a leg and gains a nurse to love. The other, the Jesus of Suburbia on 2004's "American Idiot" album, renamed Johnny, picks up a dope habit and girlfriend, loses the latter because of the former and winds up right back where he started. He comes home, along with his friends, emboldened with a new sense of personal responsibility.

The story contains almost no spoken dialogue-instead, it's told mostly through songs from "American Idiot" and its 2009 follow-up album, "21st Century Breakdown." There is a band onstage, and though the songs are sonically fuller and richer as adapted for the theater, they still retain the scrappy quality of the originals.

Watch the Billboard interview with the cast of "American Idiot"

The ending isn't exactly a happy one, but it's not King Lear, either, at least according to Green Day frontman Billie Joe Armstrong.

"The characters all made mistakes and learned lessons," he says. "It's still the beginning of a journey for them. For Johnny, he doesn't blame everything on his parents or society anymore, and he can move forward."

While the show tells the story of Johnny's transition, it also represents the maturation of Green Day. When the band first broke out of the Bay Area with snotty three-chord punk in the early '90s, the last place anyone would ever expect to see it would be on the Great White Way. But as "American Idiot" adeptly demonstrates, things rarely turn out the way you think they will.