The Muses have inspired artists and dreamers from Homer to Sonny Malone, the aspiring discotheque owner from the 1980s flick Xanadu. Once, an R-rated (for harsh and repetitive street language) musical written and directed by John Carney, trails the quirky one-week encounter between a street-singing vacuum repairman and the immigrant-muse who prods him into serious pursuit of a music career.
The pair, known only as Guy and Girl, meet on the streets of Dublin. After tipping him for his singing, she discovers that he also repairs vacuums. She sees him again the next day so that he can fix her Hoover. Guy (Glen Hansard of Irish rock band The Frames) discovers that Girl (Czech-born Markéta Irglová) practices piano at a music store over lunch breaks. Guy plays one of his songs ("Falling Slowly"), and she plays along to his guitar. This encounter sparks a flurry of songwriting and playing give-and-take, with the unlikely muse becoming just the sort of inspiration Guy desperately needs.
This song, their first collaboration, encapsulates the tension in Once. Both characters battle domestic and artistic demands. Guy works with his father and feels accountable for his happiness. His first muse, an unfaithful ex-girlfriend, haunts him. Girl supports her mother and young daughter after leaving a husband in the Czech Republic.
As they work together, Guy begins to fall in love with his muse. But unlike other movies about women and inspiration (Shakespeare in Love and Music and Lyrics, for example), their relationship does not lead to romantic fulfillment. Guy and Girl's feelings for each other are something more than platonic, but Girl remains faithful to her husband.
Musical numbers in Once flow organically; like the characters themselves, they are works in progress. Writer/director Carney illustrates how a one-time encounter can change the course of not only the artist's life but also that of the muse-and likely for the better.