The idea of the musical has changed dramatically in the last decade, between the brilliant re-stagings of Sweeney Todd and Company by director John Doyle, to the Latin-inflected, many-peopled production of In the Heights, to the bawdy and hilarious (though secretly old-fashioned) fun of The Book of Mormon. Now, the show that took home the Tony Award for Best Musical in 2012, Once, has arrived in San Francisco with its first touring cast, and it's an opportunity to see yet another, innovative new riff on the traditional form of musical theater.

Like those Doyle-directed productions, there is no on- or off-stage orchestra accompanying the performers — the performers themselves double as musicians, and spend almost every minute of the show on stage together with their instruments. The play is based on the acclaimed 2007 Irish film of the same name that follows two actual musicians, Glen Hansard and Marketa Irglova, as they meet, make music together, and fall in love despite themselves and other people in their lives. The two had performed together previously under the name The Swell Season, and wrote all the music for the film, and the subsequent musical.

Neither character is ever given a name. It's just Guy and Girl. In the musical, he is an Irishman with a girlfriend who's left Dublin to live in New York, and has started seeing someone else. She is a young woman from the Czech Republic, living with her family, too poor to afford her own piano so she borrows one from a music store in the neighborhood. Crushed by his lost love, he's discouraged from ever making music again until he meets the Girl, who insists on paying him to fix her vacuum by playing him a song she wrote. They share music, he clumsily hits on her, she pushes him off but decides to help him record a demo. Together with the help of some friends, they do just that, and magic is made.

This cast does an excellent job conveying that magic, as well as recreating the naturalism and rawness of the performances of the original film in a stage setting. Particularly astonishing is the easy chemistry between the two leads, Stuart Ward and Dani de Waal, who both come from the UK. There are more songs here than in the film — which, by the way, took home an Oscar that year for Best Original Song — and they are equally powerful, honest, and brutally emotional pieces of music, inflected with both rock-and-roll and an Irish folk sensibility.

And several ensemble numbers, including the Act 1 closer "Gold" (shown partly in the video below), are especially powerful, with simple choreography by Steven Hoggett and the sheer force of a dozen and a half voices and their respective instruments at work.

The elegant and worn-in set by Bob Crowley, made up primarily of framed mirrors and Edison bulbs like the back room of a pub, is also a beauty, and won Crowley a Tony as well. And throughout the show, the actors serve as stagehands as well, shifting chairs and other set-pieces around to convey different settings, before returning to their seats around the perimeter.

It's no wonder that this experimental, original, stripped-down show, showcasing a set of gorgeous songs that are set to a beautifully written, spare, and believable plotline, won as many accolades as it did. And you shouldn't waste any time in getting tickets.

Once plays through July 13. Get tickets here.