"Once," the 2007 film written and directed by John Carney, structured around the music of Glen Hansard and Markéta Irglová (who perform together as the Swell Season) was something of an interesting choice to adapt to the Broadway stage. The movie ostensibly only has two real characters (who don’t even have names) and follows a very loose plot about the pair creating an album together.

In order to translate the quirky, independent film to the stage, Irish playwright Enda Walsh made some significant changes to the main characters while adding in some supporting cast, in the process moving the plot towards a more clichéd romance than the movie portrays. Fortunately, though, it maintained much of the charm of the film version and proved both a commercial and critical success, garnering several Tony Awards in the process, including for best musical.

Zach Theatre’s new production of "Once" plays into this charm, with a visual and auditory feast that pays tribute to the strength of Hansard and Irglová’s music through some incredibly powerful performances, even if the script is at times lacking.

Director Dave Steakley’s staging of "Once" is deceptively simple. While much of the heart of the play comes down to scenes of two actors alone on stage talking, the rest of the show is extremely stylized, featuring a full cast of highly talented actor/musicians providing spirited musical transitions from scene to scene. The fluidity of the production is aided in no small part by Donald Eastman’s evocative, multi-purpose scenic design (inspired by McSorley’s Old Ale House in New York) and Sarah EC Maines’ evocative, saturated lighting design.

The biggest weakness of "Once" as a stage musical is the narrative traps it falls into during the first act, which very much unfolds from the perspective of the nameless Guy (played with brooding intensity and a deliciously deep voice by Corbin Mayer), a vacuum cleaner repairman and street busker dealing with a deep depression in the aftermath of a breakup. Into his world comes Girl, who turns his life around and helps him feel passionate about his music again, even going so far as to set up a studio recording session for him. This first half, then, very much evokes the tired cliché of the “manic pixie dream girl,” whose purpose in the plot is to inspire the male protagonist.

Fortunately, Girl’s role in the second act is much stronger, which takes her perspective much more strongly and allows us to see the nuance and depth that Olivia Nice brings to the role. Though she is endearing and hilarious throughout, in the second half we also realize that she, too, is enduring a great deal of pain trying to come to terms with the haunting ghosts of past love.

In many ways, though, the story of "Once" is secondary, just a layer of trappings to surround a sumptuous feast of profoundly moving musical performances. It is perhaps the best-sounding production that Zach has staged in many years and is a tribute to the ways in which music and emotion are inextricably linked together in our hearts.